CAS authentication email attribute problem

[kos giannop]

Hello, I have setup CAS on hawthorn.1 (native install) and I am able to login through the CAS on the EDX. But the email attribute is not get passed from the CAS to the edx, so the local edx user account, is created with an empty email. The next user that tries to login, attempts to be created locally on edx with an empty email as well. 

So edx does not let two users to be registered with the same email, which in my case is empty.

How can I map the correct email attribute that the CAS returns, to the edx?

Alternatively, how can I disable the duplicate email check when local edx users are created?

This is urgent. Thank you