[Building Sakai] Sakai + CAS: the user is valid but does not existed on Sakai

[Thach Le]

Dear all,

I have deployed the sakai + cas (for authentication). My CAS performs
the authentication by email such as Gmail.
The email is the user in the sakai. The sakai could not perform
"login" if the user (in this case the email) does not existed in the
database.

My temporary solution is: after the cas validated the email and
password on the Gmail server, insert an new user of that email into
the sakai's database.

It's working but I don't think this solution is well.

Are there any other solution?

Thach