He wants to duplicate his forum so when you click a 2nd forum tab you get sent to the dup.
This was discussed a bit a while back. Too many technical issues besides hitting a gray area in the license.
what is best in your position is to have a main forum that is not active... it will not show in the main page of the site *(forumhome) but you can use its url to add it to a tab so your members can access it by using the tab...