php include within a vBullitin template?

[lightnb]

I'm trying to replace the logo on my vBullitin site with a <?PHP include_once tag, so that I can use my global mast head as the header for the forums too.

I get nothing when I replace the default:

<a href="$vboptions[forumhome].php$session[sessionurl_q]"><img src="$stylevar[titleimage]" border="0" alt="$vboptions[bbtitle]" /></a>

With:

<?PHP include_once('http://www.rahlentertainment.com/livexchange/header.html');?>

Any ideas?

Thanks,

Nick