Connecting to Xbox Live Through a Dongle?

I have a T-Mobile Dongle with a PC on Windows 7. I want to connect my xbox to my dongle so i can use Xbox Live through it. I've followed tutorial after tutorial and what they say to do, some of the options are not avaliable to me. For example, on the dongle settings the ''home network connection set to local area connection' in sharing isn't avaliable? Can someone help me? i'd really appreciate it.

Suggestion:

1)First of all ,connect your desktop computer or laptop to internet with USB dongle.

2)Connect your computer and Xbox with the Ethernet cable.

3)Take Control Panel> Network and Sharing Center > Manage Network Connections

4)Enable sharing on your internet connection.Also tick the checkbox for 'Allow other network users to connect through this computer's connection' and select 'Local Area Connection' for the 'Home networking connection' menu.

5)Test your Xbox live connection and check whether it succeeds to connect to internet.(If not make both connections to public instead of private)

6)If it fails again,then restart your PC first and then turn on your Xbox.(in case of dns failures)