[kh99]

You could edit the file search.php and around line 366, make this change (add the part in red):

	if (!VB_API)
	{
		$vbulletin->url = 'search.php?' . $vbulletin->session->vars['sessionurl'] .
			"searchid=" . $results->get_searchid();
	    if (isset($searchterms['query']))
			$vbulletin->url .= "&terms=".$searchterms['query'];
	}
	else

I've only tested it by running one query, so I'm not 100% sure there aren't any problems with it.