Oh sorry I misunderstood the question. Try something like:
Code:
<tr><td class="vbmenu_option"><a href="$vbpage$session[sessionurl]&styleid=21&{$_SERVER['QUERY_STRING']}">Teatro Grottesco</a></td></tr>
{$_SERVER['QUERY_STRING']} should give you the extra reference variable things that you want. I'm not sure whether there maybe security implications or not for this.