Another option that may work for you is to login to the BlueCurve, and see if it allows "passthrough". If it does, then if you get a "second IP-address" from Shaw, you can configure Passthrough to allocate that additional IP-address to the Ethernet port that connects to your XBOX. In this mode, there is no need to configure "port-forwarding" within the BlueCurve -- your XBOX is DIRECTLY connected to the Internet.
