Bridging on a Mac

I've been connecting to Xbox Live on my Xbox 360 through my MacBook pro, as my flat has a wireless network and my Xbox 360 uses my laptop's wireless card to connect.

I have a BT Homehub and the NAT settings are set to strict - I want it to be set to open for speed of finding players and to make sure there are no strange problems during games.

I refer to THIS article.

It says, "Please note these instructions will NOT give you an Open NAT if you are connecting the Xbox to a wireless PC/Laptop and using ICS (Internet Connection Sharing).

You must be connected direct to the Homehub via ethernet or wireless, if you connect to a PC you must use Bridging."

I posted a topic on the xbox website but nobody knows what the Mac equivalent of bridging is. Can someone please tell me how to do it so I can set my NAT to "open"?

Thank you!

My guess is Apple omits this feature so that you'll buy an Airport Express or AP Extreme. There isn't even the option for WPA or WPA2 for security, just WEP.