The CB Forum tab is specifically designed to output like that. There's no functionality to do that. You can try constructing the HTML in a Custom HTML field, which may cause CB to bind to it like any other tab output. Example as follows.
Code:
<div class="cbTabs" id="cbtabsCUSTOM">
<ul class="cbTabsNav nav nav-tabs">
<li class="cbTabNav" id="cbtabnavCUSTOM1">Tab 1</li>
<li class="cbTabNav" id="cbtabnavCUSTOM2">Tab 2</li>
<li class="cbTabNav" id="cbtabnavCUSTOM3">Tab 3</li>
</ul>
<div class="cbTabsContent tab-content">
<div class="cbTabPane tab-pane" id="cbtabpaneCUSTOM1">
THIS IS TAB 1
</div>
<div class="cbTabPane tab-pane" id="cbtabpaneCUSTOM2">
THIS IS TAB 2
</div>
<div class="cbTabPane tab-pane" id="cbtabpaneCUSTOM3">
THIS IS TAB 3
</div>
</div>
</div>