I assum you are using SP1 with Simon Telephonics, do the following:
In Service Providers > ITSP Profile A > General
SignalingProtocol > SIP
In Service Providers > ITSP Profile A > SIP
IN ProxyServer, RegistarServer and OutboundProxy enter the SimonGateway server address such as
gvgw4.simonics.com or whatever they assigned.
In Voice Services > SP1 Service > Sip Credentials
AuthUserName (yoyr Simon Gateway Username such as GV1xxxxxxxxxx)
AuthPassword (secret from the Simon Gateway credentials)
That should do it... Reboot and enjoy.
CNAM should work. It does for me.