Hello, I'm a voip specialist with 10+years of experience working on the level2/NOC department of a US voip company; I can install, troubleshoot and customize many SIP devices including: softphones, ATAs, IP-phones and PBX systems like Asterisk/FPBX. I read your project description and I can certainly help you setup your FPBX to accept webRTC. Feel free to contact me at any time.
Thank you.