I have not done this so this is just based on a few minutes of digging...
Looks like you would need to edit
"viewtopic_body.tpl"... near line 29 (in 2.0.20 anyway) you will see fields like {postrow.POSTER_NAME}...
you will want to add in the correct spot a new variable like {postrow.NEW_POST_INFO} ... name and correct spot up to you
Then go into viewtopic.php and create that variable... near line 1158 is where the "postrow" variable is being defined... somewhere before that you need to do the SQL for the data... plug that into a temporary variable (say $newPostInfo) then assign inside that $template->assign_block_vars call...
'NEW_POST_INFO' => $newPostInfo,
All the CB reg stuff should be in the jos_comprofile table under that user's ID...
Hope this helps,
Greg