@LuckyMe: you can do it by specifying some attributes
code:
<Button AccRole=57 Class="TransparentButton" Layout=flowlayout(0,2,0,2) Active=MouseandKeyboard|NoSyncFocus Padding=rect(5,4,5,4)>
<urlelem AccDesc="whatever =P" AccName="whatever =P" Tooltip=true class="CommonLink" url="http://foro.msgpluslive.es/" layout=flowlayout(0,2,0,2) AccRole=57>
<element class="ToolbarIcon" content=rcimg(59001)/>
</urlelem>
</Button>