members profile link changing subdomain

[30et]

Hi,

We have put vbulletin onto different server to our regular site.

The regular site's server is an apache server, with its url www.server.com and the server with vbulletin is forum.server.com

We use a reverse proxy to redirect our users to it, so that the url remains the same.

This works fine except for when a user clicks a link to view a members' profile. Then instead of displaying www.server.com the url in the browser changes to forum.server.com

Why is this, or how can I make sure it doesn't change the url to forum.server.com?

--------------- Added [DATE]1296531025[/DATE] at [TIME]1296531025[/TIME] ---------------

The links are of the form ..

<div class="lastpost_user" style="white-space: nowrap;">
by <a href="member.php?find=lastposter&amp;f=205" rel="nofollow">RaryGirl</a>


and the htaccess file that redirects people is

<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

Options +FollowSymLinks
RewriteEngine On
RewriteBase /
RewriteRule (.*)/? http://forum.server.com/community/forums/$1 [P,L]

--------------- Added [DATE]1296544444[/DATE] at [TIME]1296544444[/TIME] ---------------

I had a look around the vbulletin files and I saw in includes/functions.php at about line 3080 there is a function exec_header_redirect($url)

This function is 'Halts execution and redirects to the specified URL invisibly'

It looks like it redirects with the php code

PHP Code:

header("Location: $url", 0, 302); 


Could this be redirecting within the same server and therefore not activating the reverse proxy?
If so how should I change the code? I could change this function or I could change all instances that call this function somehow.

--------------- Added [DATE]1296601226[/DATE] at [TIME]1296601226[/TIME] ---------------

I figured out a solution -
I changed that header location line .. I use a str_replace command to replace 'forum.' with 'www.' and that works.