what needs to be modified so that the users can register using either number or alphanumerical username? I want to be able to use either name or number for registration, and perhaps for authentication too.
I do not understand the use scenario.
all users have addresses like user@example.com. the same user has an alias like 5551234@example.com (for UAs that cannot handle alphanumerical addresses).
some UAs will send a REGISTER with a To: of user@example.com, some with a To: of 5551234@example.com. both REGISTERs needs update the location records of user@example.com. rewriting 5551234@example.com to user@example.com for INVITE et al can be handled using enum and/or normal alias lookup.
the authentication user could always be required to be user@example.com, but I guess that should be handled separately.
I have a feeling this should be handled like a normal alias on REGISTER processing + allowed 3rd party register.
jakob