I just had a look, and those template hooks aren;t there. Try editing the postbit and postbit legacy templates and adding the following code at the end of the template and see how that goes (try both to see how it looks)
Code:
<vb:if condition="$post['isfirstshown']">
{vb:raw ad_location.ad_showthread_firstpost_start}
{vb:raw ad_location.thread_first_post_content}
</vb:if>
<vb:if condition="$post['islastshown']">
{vb:raw ad_location.thread_last_post_content}
</vb:if>