[SR-Users] Proxied authentication

[Pete Ashdown]

I'm having trouble divining the proper way to authenticate calls to
remote destinations that require it.  I'm hoping someone can clear it up.

Freeswitch client server A is authenticated to Kamailio.
Freeswitch test server B is authenticated to Kamailio.

Calls from A -> Kamailio -> B fail with rejection of the authentication
information that A is using to Kamailio.

As far as I understand, I need to rewrite the authentication information
with UAC?  However, UAC's uacreg table seems to tie remote users to
remote destinations, when all I want to do is authenticate all calls
routed to the destination regardless of what the user or the source is. 
Am I using the wrong module?