I implemented it using this:
<blockquote class="vbquote" cite="showthread.php?$session[sessionurl]p=$postid#post$postid">
<div>
<cite><a href="showthread.php?$session[sessionurl]p=$postid#post$postid" rel="nofollow"><phrase 1="$username">$vbphrase[originally_posted_by_x]</phrase></a></cite>
$message
</div>
</blockquote>
I don't remember if I made that blockquote class or if it was already in use.
the only problem is that it'll say "originally posted by USER" (linked to the post) but if you don't specify a user in the quote tag, it'll still say "originally posted by" and the link will be dead. A simple if wrapped around that would clear it up, but I never tried :P