Automatically add forum user

[beltane]

Hi there,

I'm wanting to use vbulletin for an existing site I have, with a pre-existing member login. I want to create a new forum registration with the same username/password when someone joins the main site, but after that the accounts can be seperate. From my understanding, this could be done by an SQL insert statement in my existing registration, but I'm not sure if this is possible with vB? I can get the password in plain text using $_POST.

I'm keen to get started and I've read a few posts on here from my search, but I'm not 100% sure it's possible.

(I also posted this on vbulletin.com, apologies if they're related sites, I'm very new to vB!).