Combat Flight Simulator 3 UDP Ports on Vigor 2600 Plus-Help?

I am currently immersed in Combat Flight Simulator 3 (CFS3) on the internet using the multiplayer facility. I am on ADSL 512k and have a Draytek Vigor 2600 Plus router. I can see all current games and in most cases can join them and fly to my hearts content. From a simple point of view, this means there are no ports being blocked for CFS3 normal play. However, this is not true for hosting! I find that if I try to host a game, I can set it up, and everyone including myself can see it correctly, but no one can join to fly. Presumably there are some different ports that need opening to allow others to come through the firewall and join the game.

I have found the following information information on the web:

"If you cannot "see" the CFS3 Game List, and your computer is behind a Network Address Translation (NAT) or firewall machine, try opening ports on your firewall to enable gameplay. Specifically, in the Setup of your NAT/firewall, assign the following trigger ports to the coinciding public ports (note that all transmission is done using the UDP protocol).

Trigger port Public port Protocol
2300 28883-28886,2300 UDP
28883 UDP 28883-28886,2300 UDP
28884 UDP 28883-28886,2300 UDP
28885 UDP 28883-28886,2300 UDP
28886 UDP 28883-28886,2300 UDP "

If this applies to my problem, is there anyone on this forum that can offer advice and tell me how to set up the above ports on the vigor 2600 router, because the tables and information given above do not correspond to the configuration tables in the router.

Forgot to say: Using Windows XP Pro SP2, and have tried with the microsoft Firewall on and off.

Thanks in anticipation