Sorry, I just checked that template - that's not what I was looking for. We have a system running that bypasses that template in order to use a site-wide database. Works like this: a user tries to login, vbulletin checks against our database, and if that username and password matches, our database outputs username and password to vBulletin's database, and - I suspect - a range of options that the original programmer didn't quite think through.
What does that output look like, does anyone know?
From the template Xenon referred to, I suppose I just need to add "receivepm=yes" to the add-line or something like that?