Well, i couldn't just wait... hahah So i hacked it myself...
Near the end of showflat.php where you did your mods, here is what I placed... This is how it looks in mine now:
// --------------------------
// Are we ignoring this user?
if (stristr($user['U_Ignored'],"-$usernum-")) {
$postrow[$i]['Body'] = $ubbt_lang['IGNORING'];
} else {
//-------------------------------------------
// SHow only to reg users, mods, admins, and supporters
if ( ($user['U_Groups'] == "-5-") || ($user['U_Groups'] == "-6-") || ($user['U_Groups'] == "-7-") || ($user['U_Groups'] == "
-8-") || ($user['U_Status'] == "Administrator") || ($user['U_Status'] == "Moderator") || ($user['U_Status'] == "User") ) {
// Show Entire Message
$postrow[$i]['Body'] = ($Body);
}
// Show Only X Amount of Characters
else {
$postrow[$i]['Body'] = substr($Body,0,250) . "<br><Br><br><b>.... MORE</b><br><Br> To view the rest of this
post, please <a href="http://www.atvcanada.ca/newuser.php">click here to register for a FREE account.</a><br><Br>If you already h
ave an account with us, <a href="http://www.atvcanada.ca/login.php">Login</a> now.";
}
}
// -------------------------------------------------
// Only certain options for users that are logged in
Since I am not using articles, I just used it stock... The groups shown are my supporting groups, and I had to change "Users" to "User" for it to work on my board's reg'd users.
Now all un-reged users will see the register message when they read ANY posts on my site... Mission accomplished... (Well, almost... Just have to mod showthreaded...)
Deej
log into an account and you will see them 
