[AG-TECH] issue with video

we have a system that is using NAT. The audio is working fine but the video is not working at all. We send Jimmy the video but never receive anything back. He never receive video and we never receive his. We have looked at our firewall and we are not blocking anything. It appears that the bridge tries to use our internal ip address and it can not send it back on that address. is there somewhere in for software or a config file I could change to set the system to understand NAT addressing and start using our external address?