[kh99]

It looks like the keywords and description are set in a plugin ousing hook global_state_check (that's part of the blocg product). The code looks like this:

if ($vbulletin->GPC['blogid'] AND $GLOBALS['bloginfo'] = verify_blog($vbulletin->GPC['blogid'], false, false))
{
	$GLOBALS['blogid'] =& $GLOBALS['bloginfo']['blogid'];
	$vbulletin->options['keywords'] = ($GLOBALS['bloginfo']['taglist'] ? $GLOBALS['bloginfo']['taglist'] . ', ' : '') . $GLOBALS['bloginfo']['title'] . ', ' . $vbulletin->options['keywords'];
	$vbulletin->options['description'] = $GLOBALS['bloginfo']['title'] . ' ' . $GLOBALS['bloginfo']['blog_title'];
}

So it might work if you were to create your own plugin using that hook, and set the execution order to something > 5 to make sure it runs after the existing plugin. Then do something like:

	
if ($vbulletin->GPC['blogid'] AND $GLOBALS['bloginfo'])
{
	$vbulletin->options['keywords'] = ''; // of course you can set these to whatever you want instead of a blank string
	$vbulletin->options['description'] = '';
}