Just go to your navbar template and find this code (in a couple places):
HTML Code:
<td class="vbmenu_control"><a href="search.php?$session[sessionurl]do=getnew" accesskey="2">$vbphrase[new_posts_nav]</a></td>
And replace it with this code:
HTML Code:
<td class="vbmenu_control"><a href="search.php?$session[sessionurl]do=getdaily" accesskey="2">$vbphrase[todays_posts]</a></td>
I think that will do what you want.