Changing H-tag in responsive Tab

Hi,
i am trying to replace the h-tag with <div> in the responsive tab version. I replaced it in the .php (includes/shortcodes/vc/boc_tabs.php) but it didnt make a change in the responsive version! Could you give me a hint where i can find the right spot?
<h2 class=”resp-accordion resp-tab-active” role=”tab” aria-controls=”tab_item-2″><span class=”resp-arrow”></span><span class=”icon icon-clock”></span>…</h2>

Thanks alot!
Best Regards