Forum Adding sub links to the"Forum" tab?
 

I'd like to add sub-links to the sub-menu of the default "Forum" tab, but I'm not exactly sure how I would go about doing this. I have the Tabs Add System for vBulletin 4 modification, however that mod (to my knowledge) doesn't have the option to add sub-links to default tabs.

For reference, this is the "sub-menu" I speak of (outlined in red):

http://img243.imageshack.us/img243/8858/61342999.jpg

tl;dr: how do I add links, or "sub-links," to the "sub-menu" of a default tab?