MSN Video Conversation won't work in my home network

[Cronqvist]

Hi

I have a little network. I use a Windows XP as the
gateway/server. The gateway is connected to the Internet
through a router. UPnP is enabled on the router. If I use
MSN Video Conversation directly on the server, I have no
problem making it work, but if I try using MSN Video
Conversation from one of my clients (WinXP) connected to
the gateway, it won't work...the connection with the
remote computer fails. The gateway/server is running
Internet Connection Sharing and Internet Connection
Firewall. I have tried to disable the firewall on the
server with no result. What am I doing wrong?

Thanx in advance

Michael Cronqvist