Port forwarding instead of IP Passthrough

I have set up a game server for jedi knight jedi academy but when I set up port forwarding in my router/modem (westell Versalink 327w) I can only see the server by using my internal IP and I see my network places. When I set up IP Passthrough I can see the server through the external IP but but I lose my network places. I dont want to lose network places but I also dont want my internal Ip posted on the internet for people to gain acces to my server.
Can anyone help me out with this???