I tried to host the game behing a firewall and tried out every portmapping I could find.

To get to the point, I can host the game with no problems if I use the game (and CD). But I can't host it if I try the dedicated server with the same settings on the same machine. Yeah it's running, but nowhere on the internet is it visable. The game CD hosting is visable within minutes.

So my conclusion is that there is a difference between hosting the game. Is the game CD designed to host behind a firewall?
And the dedicated server not?

Do you have to put the external IP adres somewhere in the dedicated server?
Is there any command in the dedicated server command line that does that?
I'm stucked here and don't want to use the CD only for hosting.

And I don't understand why there's a difference between hosting the dedicated server or the game CD. Why is it not the same code?

What program are you using to for the dedecated server? Give the file or shortcut name. Does it work when you turn your firewall off?