external register and login possible?

[Kyo-dono]

Hello. I have a website without a forum but above 1000 active users. Now i think to add vBulletin or SMF2.0. vBulletin is my favorit but can vBulletin this too?

1. How add new users to vBulletin with a external php script?
I want add my 1000 users per script to vBulletin database and in future use my own register formular to register simultaneous in vBulletin too.

2. The forum is only a addon for my page, so i want login and logout with my own user-management-system. How can login and logout simultaneous in vBulletin with a external php script? So that the user is login in my website and a script login him in vBulletin too, without visit the vBulletin folder.

I hope anybody understand my questions and can help me with it.