[Marco van Herwaarden]

It is done by a piece in global.php:

PHP Code:

// #############################################################################
// Redirect if this forum has a link
// check if this forum is a link to an outside site
if (trim($foruminfo['link']) != '')
{
    // get permission to view forum
    $_permsgetter_ = 'forumdisplay';
    $forumperms = fetch_permissions($forumid);
    if (!($forumperms & $vbulletin->bf_ugp_forumpermissions['canview']))
    {
        print_no_permission();
    }
    exec_header_redirect($foruminfo['link'], true);
} 


I don't have time to look for a solution now, but this should get you going.

1 Thing is strange though (a bug??), it is passing a second parameter to exec_header_redirect (true), but this function don't take a second parameter i think.