No you cant!!
You need some sort of modification to include in your portal page and I dont use Invisionboard so I cant tell you where or what to edit to get it there.
The link I provided you will get you started.
You basically need to modify of included block for vbulletin removing any
vb stuff in there.
You can then include and echo contents of that file where ever you wish like so
Code:
Content visible to verified customers only.