As I posted over on vb.com, you'll need to use $post or $userinfo. However, the code you posted over on vb.com isn't going to work as is. You have a bunch of variables in it that aren't defined for use in the postbit. You will have to simplify it quite a bit.
edit: Someone posted this in another thread. It may work for you:
HTML Code:
<div>$vbphrase[last_seen_online]: $post[lastseen_date] $post[lastseen_time]</div>
You may have to create that phrase or just use text. And, I'm not sure if those are actual working variables or ones he created using a plugin. Try substituting variables that you were going to use in there.