IAX: Support for autentication through LDAP server

Hi all,
I’m involved in a project, in my university, concerning a VOIP framework. We want to offer a VoIP service to all studends by using: asterisk, a customized iax client. Inside the university we have an LDAP server that hosts all profiles of students so we thought about using it to gain information during the login process. As far as I know the SIP protocol in asterisk supports authentication with pam and radius and both are good possibility to reach an LDAP server.
I was wondering why iax doesn’t support it, and eventually is there any possibility to implement it easily, since we don’t want to use SIP for the well known problem of NAT

Thanks in advance

Greetings

Ciro Guariglia, Italy