If you create a permit policy to the phone ip address and turn on logging the log will name any alg that is applied to the traffic. This will let you know if processing by one of the alg is indeed the issue and which one to turn off.
You could also try putting the application type on that policy to "ignore" instead of the default "none". This turns off processing of all alg for that traffic. But if you need the alg to apply then it won't work.
Steve Puluka BSEET Juniper Ambassador Senior Network Engineer - UPMC Pittsburgh, PA JNCIA-ER JNCIA-EX JNCIS-SEC JNCIP-SEC JNCIS-FWV JNCIS-SSL MCP - Managing Server 2003 MCP - Windows XP Professional MCTS Windows 7 http://puluka.com/home