Need to bypass vBulletin login with my own login

[jejjcop]

Hi,

Im running a social networking website and I now, after having purchased vBulletin, need to integrate it into my social networking website.
With vBulletin you need to log in to the forum to be able to post etc.......since my users are already logged into my site at that time I do not want them to have to log in again.
Can this be done?

I store these variables:

$_SESSION['userNr']
$_SESSION['username']

Thanks
Jejjcop