User delete

Hello guys

Im using wordpress 3.0.4 with multi site installed.

And I have a problem… when I delete one user it get deleted from user part but not from global user… only super admin can see that this user doesn’t have one website related.

Is there one way to use wp functions that delete user from users like remove him totaly from the DB?????

Because user can try to create an new account… but since its not deleting from all sites at once… I can’t recreate the account using same mail.

Any advices???

Thanks,
Thiago Cruz