[Da-Vinci]

I'm not sure if this will work, but I have my site go to a custom VBA portal page, what I did was opened the index.php in my forums root and changed,

/**
 * Use the forum as the default script:
 */

require('forum.php');

around line 63, to

/**
 * Use the forum as the default script:
 */

require('portal.php');

so my guess is, if you change,

require('forum.php');

to

require('forumdisplay.php?2');

you should get the desired effect.