Simple modal login and buddypress.. registration fails

I need some ideas or a solution to a problem I'm having on a site. My theme uses the plugin simple modal login for login, facebook connect and ordinary registration.
Login and facebook connect works perfect. But the ordinary wp/buddypress registration fails.

The registration is wp style with a username and email field - password is generated and send to e-mail.

But buddypress registration is a bit different. Here you have to choose your own password and then active account by clicking link i email.

Could the problem be that the buddypress registration somehow interfere with the modal registration?

Is there a way to completly turn of buddypress registration and only use the wp-login?

Any other ideas to fix this conflict?

The simple modal registration works fine if I deactive buddypress. I'm kinda lost, have working on this for days to fix, but no luck :disappointed: