Trixbox and IPCop - Phones from remote locations

[crash848]

I've got a problem, I have a Trixbox setup on my orange subnet of my IPCop. (See network "diagram" below). It works great from inside the firewall, and over site to site VPNs. I can call out to a SIP provider and can call in from them as well. The only issue I am having is with phones registering to the external IP address (see configs below as well). They register with the Trixbox fine, will ring and can place a call, but no audio in either direction. I've scoured the internet with no luck on any of the fixes. Here is what i have done so far:

o Forwarded ports TCP/UDP 5060 - 5082, and UDP 10,000 - 20,000 to my Trix (192.168.2.200)
o sip_nat.conf is as follows:

bindport=5060
nat=yes
externhost=xxxxx.com
externrefresh=10
localnet=192.168.2.0/255.255.255.0
realm = xxxxx.com


DIAGRAM!
Internet -> IPCop (orange) -> Trixbox


Anyone who can help me out with this, please do! I can't get it to work for the life of me.