So my setup is fairly straight forward as this was a test for the AS7 firewall. As I mentioned the configuration we are used to from the v6 series is that the phones are configured to go to the address of the SIP server, the proxy was set to transparent. Allowed hosts was the Internal side, and the interface was Internet.

Before reading your note, I had the v7 configuration with the server being the IP that of the foreign SIP server, and Internet network as the client.
The firewall has one rule for MASQ of all clients on the Internal network. There are three phones at this location, but only one is enabled during the testing period. Since I do not have an inbound server and I dont have extra IPs I dont have a DNAT rule.

My packet filter rulebase is an any any allow outbound rule, with a new rule added that allows all inbound from the IP network of the SIP server.

My Internet connection type is Cable Modem (DHCP).

Still no joy on this. I am going to have pull sniffer traces to see what the firewall is producing in terms of packets.