New customer CM 4.2.(3) has set up remote site to site vpn's for users. He can register phone fine and can take calls without issue. Outbound calls get a "network busy" message. the setup is pure not cisco - "I am currrently using a Linksys WRT350N Wireless N Gigabit Router. I use it purely as only a WiFi AP. It hangs off of an HP ProCurve Gigabit Switch 2824. Also hanging off the switch is a Checkpoint EdgeBox X8 -- which provides internet and site-site VPN connectivity via Comcast"
I have read stuff on other forums about QPSS etc but this is not a roaming type issue.