Bueno te lo pondré como lo tiene mi web xd.
Yo también solía hacer lo que dice Dark Neo, hasta que me di cuenta que cuando editas la plantilla postbit_pm también se edita en /showteam.php y eso queda mal.
Remplaza tu global.css por esto:
body {
	background: #efefef url(../../../images/mycleanblue/bg.png) repeat;
	color: #000;
	font-family: Verdana, Arial, Sans-Serif;
	font-size: 13px;
	line-height: 1.4;
	margin: 0;
	padding: 0;
}
a:link, a:visited {
	color: #007ecf;
	text-decoration: none;
}
a:hover, a:active {
	color: #000;
	text-decoration: underline;
}
div#contenedor {
	width: 960px;
	margin: auto auto;
}
div#cabecera h1 {
	background: #0d0c0c url(../../../images/mycleanblue/fondo-cabecera.png) repeat-x;
	border-color: #000;
	border-style: solid;
	border-width: 0 1px;
	display: block;
	height: 60 px;
	margin: 0 10px;
}
div#cabecera h1 a#logo {
	background: url(../../../images/mycleanblue/logo.png) no-repeat;
	display: block;
	position: relative;
	width: 100%;
	height: 60px;
}
div#cabecera h1 a#logo span {
	display: none;
}
div#cabecera ul#menu {
	background: #00548d url(../../../images/mycleanblue/fondo-menu.png) repeat-x;
	list-style: none;
	margin: 0;
	padding-left: 20px;
}
div#cabecera ul#menu li {
	display: inline-block;
	margin: 6px 20px 6px 0;
}
div#cabecera ul#menu li a:link,
div#cabecera ul#menu li a:visited {
	color: #fff;
	text-decoration: none;
}
div#cabecera ul#menu li a:hover,
div#cabecera ul#menu li a:active {
	text-decoration: underline;
}
#iniciar-sesion {
	width: 350px;
	position: absolute;
	margin: 0;
	margin-left: 600px;
	z-index: 99;
}
.tborder-iniciar-sesion {
	background: #d0d0d0;
	width: 100%;
	margin: auto auto;
	border: 4px solid #00548d;
	border-top: 0;
}
div#contenido {
	background: #fff;
	border-color: #ddd;
	border-style: solid;
	border-width: 0 1px;
	margin: 0 10px;
	padding: 15px;
}
div#pie {
	background: #b5b5b5 url(../../../images/mycleanblue/fondo-pie.png) repeat-x;
	border: 1px solid #ccc;
	border-bottom: 1px solid #aaa;
	padding: 6px;
	overflow: hidden;
}
div#pie span#powered-by, div#pie span#created-by {
	color: #666;
	font-size: 0.7em;
}
div#pie span#enlaces {
	float: right;
	color: #666;
	font-size: 0.8em;
}
#panel {
	background: #efefef;
	color: #000000;
	font-size: 11px;
	border: 1px solid #D4D4D4;
	padding: 5px 8px;
	margin: 0 10px;
}
#panel .remember_me input {
	vertical-align: middle;
	margin-top: -1px;
}
table {
	color: #000000;
	font-family: Verdana, Arial, Sans-Serif;
	font-size: 13px;
}
.tborder {
	background: #d0d0d0;
	width: 100%;
	margin: auto auto;
	border: 1px solid #007ecf;
	padding: 1px;
}
.tborder2 {
	background: #efefef;
	width: 100%;
	margin: auto auto;
	border: 1px solid #d4d4d4;
}
.thead {
	background: #00548d url(../../../images/mycleanblue/thead_bg.gif) top left repeat-x;
	color: #fff;
}
.thead a:link, .thead a:visited {
	color: #fff;
	text-decoration: none;
}
.thead a:hover, .thead a:active {
	color: #fff;
	text-decoration: underline;
}
.tcat {
	background: #bdbdbd url(../../../images/mycleanblue/tcat_bg.gif) top left repeat-x;
	color: #000;
	font-size: 12px;
}
.tcat a:link, .tcat a:visited {
	color: #007ecf;
	text-decoration: none;
}
.tcat a:hover, .tcat a:active {
	color: #000;
	text-decoration: underline;
}
.trow1-foro {
	background: #f7f7f7;
	width: 100%;
}
.trow2-foro {
	background: #e8e8e8;
	width: 100%;
}
.trow1-foro:hover, .trow2-foro:hover {
	background: #dff7ff;
}
.trow1 {
	background: #f5f5f5;
}
.trow2 {
	background: #eaeaea;
}
.trow_shaded {
	background: #ffdde0;
}
.trow_selected td {
	background: #FFFBD9;
}
.trow_sep {
	background: #e5e5e5;
	color: #000;
	font-size: 12px;
	font-weight: bold;
}
.tfoot {
	background: #00548d url(../../../images/mycleanblue/thead_bg.gif) top left repeat-x;
	color: #ffffff;
}
.tfoot a:link, .tfoot a:visited {
	color: #fff;
	text-decoration: none;
}
.tfoot a:hover, .tfoot a:active {
	color: #fff;
	text-decoration: underline;
}
.bottommenu {
	background: #efefef;
	color: #000000;
	border: 1px solid #4874a3;
	padding: 10px;
}
.navigation {
	background: #bdbdbd url(../../../images/mycleanblue/tcat_bg.gif) top left repeat-x;
	border: 1px solid #d4d4d4;
	color: #000000;
	font-size: 10px;
	font-weight: bold;
	padding: 5px;
}
.navigation a:link {
	text-decoration: none;
}
.navigation a:visited {
	text-decoration: none;
}
.navigation a:hover, .navigation a:active {
	text-decoration: none;
}
.navigation .active {
	color: #000000;
	font-size: 11px;
	font-weight: bold;
}
.smalltext {
	font-size: 11px;
}
.largetext {
	font-size: 16px;
	font-weight: bold;
}
input.textbox {
	background: #ffffff;
	color: #000000;
	border: 1px solid #555;
	padding: 2px;
}
textarea {
	background: #ffffff;
	color: #000000;
	border: 1px solid #555;
	padding: 2px;
	font-family: Verdana, Arial, Sans-Serif;
	line-height: 1.4;
	font-size: 13px;
}
select {
	background: #ffffff;
	border: 1px solid #555;
}
input.textbox:focus, select:focus, textarea:focus {
	border: 1px solid #007ecf;
}
input.textbox:focus, textarea:focus {
	outline: none;
}
.editor {
	background: #f1f1f1;
	border: 1px solid #ccc;
}
.editor_control_bar {
	background: #fff;
	border: 1px solid #00548d;
}
.autocomplete {
	background: #fff;
	border: 1px solid #000;
	color: black;
}
.autocomplete_selected {
	background: #adcee7;
	color: #000;
}
.popup_menu {
    background: #fff;
    border: 1px solid #000;
    padding: 2px;
}
.popup_menu .popup_item {
    background: #fff;
    color: #000;
    font-size: 11px;
}
.popup_menu .popup_item:hover {
    background: #C7DBEE;
    color: #000;
} 
.trow_reputation_positive {
	background: #ccffcc;
}
.trow_reputation_negative {
	background: #ffcccc;
}
.reputation_positive {
	color: green;
}
.reputation_neutral {
	color: #444;
}
.reputation_negative {
	color: red;
}
.invalid_field {
	border: 1px solid #f30;
	color: #f30;
}
.valid_field {
	border: 1px solid #0c0;
}
.validation_error {
	background: url(../../../images/mycleanblue/invalid.gif) no-repeat center left;
	color: #f30;
	margin: 5px 0;
	padding: 5px;
	font-weight: bold;
	font-size: 11px;
	padding-left: 22px;
}
.validation_success {
	background: url(../../../images/mycleanblue/valid.gif) no-repeat center left;
	color: #00b200;
	margin: 5px 0;
	padding: 5px;
	font-weight: bold;
	font-size: 11px;
	padding-left: 22px;
}
.validation_loading {
	background: url(../../../images/mycleanblue/spinner.gif) no-repeat center left;
	color: #555;
	margin: 5px 0;
	padding: 5px;
	font-weight: bold;
	font-size: 11px;
	padding-left: 22px;
}
/* Additional CSS (Master) */
img {
	border: none;
}
.clear {
	clear: both;
}
.hidden {
	display: none;
	float: none;
	width: 1%;
}
.hiddenrow {
	display: none;
}
.selectall {
	background-color: #FFFBD9;
	font-weight: bold;
	text-align: center;
}
.float_left {
	float: left;
}
.float_right {
	float: right;
}
.menu ul {
	list-style: none;
	margin: 0;
}
.menu li {
	display: inline;
	padding-left: 5px;
}
.menu img {
	padding-right: 5px;
	vertical-align: top;
}
#panel .links {
	margin: 0;
	float: right;
}
.expcolimage {
	float: right;
	width: auto;
	vertical-align: middle;
	margin-top: 3px;
}
img.attachment {
	border: 1px solid #E9E5D7;
	padding: 2px;
}
img.attachment:hover {
	border: 1px solid #777;
}
hr {
	background-color: #000000;
	color: #000000;
	height: 1px;
	border: 0px;
}
#debug {
	text-align: right;
	font-size: 10px;
}
blockquote {
	border: 1px solid #ccc;
	margin: 0;
	background: #fff;
	padding: 4px;
	margin-left: 8px;
}
blockquote cite {
	font-weight: bold;
	border-bottom: 1px solid #ccc;
	font-style: normal;
	display: block;
	margin: 4px 0;
}
blockquote cite span {
	float: right;
	font-weight: normal;
}
blockquote cite span.highlight {
	float: none;
	font-weight: bold;
	padding-bottom: 0;
}
.codeblock {
	background: #fff;
	border: 1px solid #ccc;
	padding: 4px;
	margin-left: 8px;
}
.codeblock .title {
	border-bottom: 1px solid #ccc;
	font-weight: bold;
	margin: 4px 0;
}
.codeblock code {
	overflow: auto;
	height: auto;
	max-height: 200px;
	display: block;
	font-family: Monaco, Consolas, Courier, monospace;
	font-size: 13px;
}
.subforumicon {
	border: 0;
	vertical-align: middle;
}
.separator {
	margin: 5px;
	padding: 0;
	height: 0px;
	font-size: 1px;
	list-style-type: none;
}
form {
	margin: 0;
	padding: 0;
}
.autocomplete {
	text-align: left;
}
.subject_new {
	font-weight: bold;
}
.highlight {
	background: #FFFFCC;
	padding-top: 3px;
	padding-bottom: 3px;
}
.pm_alert {
	background: #fff6ce url(../../../images/mycleanblue/fondo-alerta-mp.png) repeat-x;
	border: 1px solid #FFD324;
	text-align: center;
	padding: 5px 20px;
	margin-bottom: 15px;
	font-size: 11px;
}
.red_alert {
	background: #FBE3E4;
	border: 1px solid #A5161A;
	color: #A5161A;
	text-align: center;
	padding: 5px 20px;
	margin-bottom: 15px;
	font-size: 11px;
}
.high_warning {
	color: #CC0000;
}
.moderate_warning {
	color: #F3611B;
}
.low_warning {
	color: #AE5700;
}
div.error {
	padding: 5px 10px;
	border-top: 2px solid #FFD324;
	border-bottom: 2px solid #FFD324;
	background: #FFF6BF;
	font-size: 12px;
}
div.error p {
	margin: 0;
	color: #000;
	font-weight: normal;
}
div.error p em {
	font-style: normal;
	font-weight: bold;
	padding-left: 24px;
	display: block;
	color: #C00;
	background: url(../../../images/mycleanblue/error.gif) no-repeat 0;
}
div.error.ul {
	margin-left: 24px;
}
.online {
	color: #15A018;
}
.offline {
	color: #C7C7C7;
}
.pagination {
	font-size: 11px;
	padding-top: 10px;
	margin-bottom: 5px;
}
.tfoot .pagination, .tcat .pagination {
	padding-top: 0;
}
.pagination .pages {
	font-weight: bold;
}
.pagination .pagination_current {
	padding: 3px 6px;
	margin-bottom: 3px;
	border: 1px solid #bababa;
}
.pagination a {
	padding: 2px 6px;
	margin-bottom: 3px;
	border: 1px solid #bababa;
}
.pagination .pagination_current {
	background: #F5F5F5;
	border: 1px solid #777;
	font-weight: bold;
	color: #000;
}
.pagination a:hover {
	background: #F5F5F5;
	border: 1px solid #777;
	text-decoration: none;
}
.thread_legend, .thread_legend dd {
	margin: 0;
	padding: 0;
}
.thread_legend dd {
	padding-bottom: 4px;
	margin-right: 15px;
}
.thread_legend img {
	margin-right: 4px;
	vertical-align: bottom;
}
.success_message {
	color: #00b200;
	font-weight: bold;
	font-size: 10px;
	margin-bottom: 10px;
}
.error_message {
	color: #C00;
	font-weight: bold;
	font-size: 10px;
	margin-bottom: 10px;
}
.post_body {
	padding: 5px;
}
.post_content {
	padding: 5px 10px;
}
.quick_jump {
	background: url(../../../images/mycleanblue/jump.gif) no-repeat 0;
	width: 13px;
	height: 13px;
	padding-left: 13px; /* amount of padding needed for image to fully show */
	vertical-align: middle;
	border: none;
}
.repbox {
	font-size:16px;
	font-weight: bold;
	padding:5px 7px 5px 7px;
}
._neutral {
	background-color:#FAFAFA;
	color: #999999;
	border:1px solid #CCCCCC;
}
._minus {
	background-color: #FDD2D1;
	color: #CB0200;
	border:1px solid #980201;
}
._plus {
	background-color:#E8FCDC;
	color: #008800;
	border:1px solid #008800;
}
.pagination_breadcrumb {
	background-color: #f5f5f5;
	border: 1px solid #888;
	padding: 8px 6px;
	font-weight: normal;
}
.pagination_breadcrumb_link {
	vertical-align: middle;
	cursor: pointer;
}
.forumbit_subforos {
	list-style: none;
	margin: 0;
	padding: 0;
	margin-top: 5px;
}
.forumbit_subforos li {
	float: left;
	width: 180px;
}
.boton {
	font-weight: bold;
	font-size: 15px;
	background: url(../../../images/mycleanblue/button.gif) repeat-x bottom left!important;
	color: #000;
	padding: 3px 8px;
	border: 1px solid #bababa;
}
.boton:link, .boton:visited {
	color: #000;
	text-decoration: none;
}
.boton:hover {
	color: #007ecf;
	text-decoration: none;
	border: 1px solid #777;
}
.boton:active {
	background: #cbcbcb url(../../../images/mycleanblue/button.gif) repeat-x top left!important;
	color: #000;
	text-decoration: none;
}
fieldset {
	padding: 8px;
	border: 1px solid #a8a8a8;
	background: #f5f5f5;
}
legend {
	padding: 1px 5px;
	border: 1px solid #a8a8a8;
	background: #ddd;
}
fieldset {
	padding: 5px;
	padding-top: 8px;
	border: 1px solid #a8a8a8;
	background: #f5f5f5;
}
legend {
	padding: 1px 5px;
	border: 1px solid #a8a8a8;
	background: #ddd;
}
		
		
css3.css
div#cabecera ul#menu,
.tborder,
.tborder2,
.navigation,
input.textbox,
.boton,
.pagination_previous,
.pagination_first,
.pagination_page,
.pagination_current,
.pagination_last,
.pagination_next,
.pagination_breadcrumb,
.pm_alert,
.popup_menu,
.popup_item,
blockquote,
.codeblock,
.adjuntos-adjunto,
img.attachment,
fieldset,
legend {
	border-radius: 5px;
	-moz-border-radius: 5px;
	-webkit-border-radius: 5px;
}
div#pie {
	border-top-left-radius: 10px;
	-moz-border-radius-topleft: 10px;
	-webkit-border-top-left-radius: 10px;
	border-top-right-radius: 10px;
	-moz-border-radius-topright: 10px;
	-webkit-border-top-right-radius: 10px;
}
.thead {
	border-top-left-radius: 5px;
	-moz-border-radius-topleft: 5px;
	-webkit-border-top-left-radius: 5px;
	border-top-right-radius: 5px;
	-moz-border-radius-topright: 5px;
	-webkit-border-top-right-radius: 5px;
}
.tfoot {
	border-bottom-left-radius: 5px;
	-moz-border-radius-bottomleft: 5px;
	-webkit-border-bottom-left-radius: 5px;
	border-bottom-right-radius: 5px;
	-moz-border-radius-bottomright: 5px;
	-webkit-border-bottom-right-radius: 5px;
}
.tborder-iniciar-sesion {
	border-bottom-left-radius: 7px;
	-moz-border-radius-bottomleft: 7px;
	-webkit-border-bottom-left-radius: 7px;
	border-bottom-right-radius: 7px;
	-moz-border-radius-bottomright: 7px;
	-webkit-border-bottom-right-radius: 7px;
}
select {
	border-top-left-radius: 5px;
	-moz-border-radius-topleft: 5px;
	-webkit-border-top-left-radius: 5px;
	border-bottom-left-radius: 5px;
	-moz-border-radius-bottomleft: 5px;
	-webkit-border-bottom-left-radius: 5px;
}
.caja-mensaje {
	-moz-border-radius: 7px;
	-webkit-border-radius: 7px;
	border-radius: 7px;
}
.popup_menu {
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    border-radius: 5px;
    -moz-box-shadow: 0px 0px 20px #777777;
    -webkit-box-shadow: 0px 0px 20px #777777;
    box-shadow: 0px 0px 20px #777777;
} 
		
		
Luego vas a Estilos y plantillas > Plantillas > Caja del mensaje - Plantillas > postbit_classic
Y buscas el código que comience con esto:
<strong><span class="largetext"><a href="{$post['profilelink_plain']}" id="miembro_{$post['pid']}">{$post['username_formatted']}
Y termine en esto:
<script type="text/javascript">if(use_xmlhttprequest == "1"){new PopupMenu("miembro_{$post['pid']}");}</script></div>
Todo eso lo remplazas por esto:
  <strong><span class="largetext"><a href="{$post['profilelink_plain']}" id="miembro_{$post['pid']}">{$post['username_formatted']}<img src="{$theme['imgdir']}/arrow_down.gif" alt="v" style="vertical-align: middle;" /></a></span></strong><br />
					<div id="miembro_{$post['pid']}_popup" class="popup_menu smalltext" style="display: none;">
							<div class="popup_item_container"><a href="{$post['profilelink_plain']}" class="popup_item"><img style="vertical-align: top;" src="http://www.soportemybb.com/images/soportemybb/postbit_profile.png" /> {$post['username_formatted']}</a>
							<a href="member.php?action=emailuser&uid={$post['uid']}" class="popup_item"><img style="vertical-align: top;" src="http://www.soportemybb.com/images/soportemybb/postbit_email.png" /> Envíale un email</a>
							<a href="private.php?action=send&uid={$post['uid']}" class="popup_item"><img style="vertical-align: top;" src="http://www.soportemybb.com/images/soportemybb/postbit_pm.png" /> Mándale un mensaje privado</a>
							<a href="search.php?action=finduser&uid={$post['uid']}" title="{$lang->find_posts}" class="popup_item"><img style="vertical-align: top;" src="http://www.soportemybb.com/images/soportemybb/postbit_find.png" /> Encuentra todos sus mensajes</a>
							{$post['button_www']}
						</div>
						<script type="text/javascript">if(use_xmlhttprequest == "1"){new PopupMenu("miembro_{$post['pid']}");}</script></div>
Luego a postbit_www y remplazas todo por esto:
<a href="{$post['website']}" title="{$lang->find_posts}" class="popup_item"><img style="vertical-align: top;" src="http://www.soportemybb.com/images/soportemybb/postbit_www.png" /> Visita su pagina web</a>
Con esto quedaría tal como lo tiene soportemybb.
Saludos!