Hi there,
I can help you with this project. It is no worries if FreePBX does not support these kinds of phones. With proper XML CNF file for each phone type, you will can have the IP phone register properly with Asterisk.
One thing to note that Cisco Phone should be on the same LAN network of Asterisk server (No NAT involved).
My bid includes setting up config files for 01x8831 and 01x8961 phones, with the xml files put in TFTP on Asterisk.
Your help is needed when I am doing the work (like booting the phone, telling me what is the status of phone etc...). It may require some tries before it works, and once it works, it works forever.
Read my positive feedback, and let me know soon.
Kind regards,
Bao