Calls through firewall only work on local Brekeke Extensions

1. Brekeke Product Name and version:
Brekeke SIP Server
2. Java version:

3. OS type and the version:
Windows 2003 Server
4. UA (phone), gateway or other hardware/software involved:
Mitel
5. Select your network pattern from http://www.brekeke-sip.com/bbs/network/ ... terns.html :

6. Your problem:
When the client is connected directly to the brekeke everything works great.

When I connect the client through firewall only calls between other brekeke extensions work. Calls routed to Mitel from Brekeke come back not found.

is mitel registered at brekeke?
who sent 404 not found?
is there any dial plan rule which will apply to the call to mitel?

Yes I can call the mitel fine when I register directly to the brekeke and not through the firewall.

When I register through the firewall mitel says not found... but network trace shows the extension is correct. I assume it is because the brekeke shows the external ip to the mitel

Do you know which part of INVITE packet sent from the Brekeke indicates the external ip address?
Can you paste the INVITE packet here?