[Users] auth_radius extra parameter

[Dimo]

Hello,
I wonder if there is a way to send an extra parameter with the
authentication request to a radius server. For example an AVP
containing the call ID.
I have a radius server which we use to authenticate only the Invites,
but not the Register requests. I would like to be able to send the
call ID as an extra parameter to the apart from the parameters sent by
the digest authentication to the radius.
I seem to be unable to find anything like that in the documentation.
I know the radius server can return a Sip AVP in the reply, i just
need a similar mechanism for the request.
Any pointers or suggestions?

Regards,
Dimitar