Vonage phone (Polycom Soundpoint 331) .. Can I use Line 2 on FreePBX?

Greetings-

I have several phones working on FreePBX (internal calls only). A few phones in my office use Vonage, they are Polycoms. I have logged into the WebUI of a Polycom Soundpoint 331 phone and attempted to configure Line 2 to connect to my FreePBX system (same subnet on the LAN here). It does not seem that the phone will even attempt registering Line 2 to my FreePBX instance. I have even used tcpdump on the FreePBX O.S. to see if I am geting any kind of connection attempt from the phone but I see nothing. I can ping the phone from FreePBX, so I do not believe it is a LAN connectivity issue.

I am wondeirng if there is some automatic provisioning from Vonage which is making the phone firmware ignore my manual Line 2 settings entirely. The settings do persist after a reboot of the phone, but still I see not connection attempt being made to FreePBX.

I have uploaded a screenshot of my Line 2 settings : http://imgur.com/aZbtXwe

Any hints much appreciated, thank you.

It is likely that Vonage locks the phones down so you cant change them.