Using vBulletin as master SSO base?

[Shamil.]

Hi, is there anyway that I could use vBulletin as a master SSO base?
such as OpenX has :


http://login.openx.org to login to the site so: https://login.thinkteen.co.uk

so that the user logs into the forum here: http://thinkteen.co.uk/forum
and the user logs onto a joomla installation or whatever (how do I do it for a custom CMS (built by myself?)) both on http://thinkteen.co.uk and http://radioteen.co.uk and then on the CMS control site: http://admin.thinkteen.co.uk?

So basically, we're looking at using the registration form and login script (from the forum index.php?) to product a cookie that will authenticate the user and login to all of the aforementioned systems/sites.

This might make it slightly more complicated, but add SSL into the mixture