Cannot establish a VoIP call

[Raziff]

I have two BCMs (BCM50 rel. 2 and a BCM400 rel. 3.7) networked via VoIP Trunks.. They are connected through an IPSec Tunnel using triple DES encryption. If one BCM tries to connect to the other, the call simply drops. If I place both BCMs on the same LAN via a switch, calls go through fine. However, through the WAN, nothing. The BCM Monitor shows the line going active for a brief period and the Target line ringing the associated set. The firewall monitor also shows the call going through and suddenly being dropped. According to the firewall monitor, nothing is blocked. Data traffic flows fine across the WAN.

BCM400:
192.168.0.250
Gateway - 192.168.0.1
Direct Mode

BCM50:
192.168.2.250
Gateway - 192.168.2.1
Direct Mode

When i tested the systems on the same LAN, the only change was the IP address on the BCM50, it was changed to 192.168.0.251 with a Gateway of 192.168.0.1.

Any help will be greatly appreciated.