We are trying to implement VOIP.MS SIP trunks and continue to receive the message "number has not yet been assigned". We can trace the call and it registers with the carrier. It looks like we are sending the internal IP address of the IP office instead of the external IP, so the carrier receives the inquiry, but can't route back to us. What setting controls the IP address that is sent to the carrier? Can someone share a working config, so I can try to figure out the mismatch.