Problem with ad hoc network

[Ethanw]

Hello,

I am trying to internet share using ad hoc. I am trying to get my Vista computer (which is connected using Dial-Up) to internet share with a Windows 7 computer. I have successfully setup an Ad Hoc network and connected it, but I cannot connect to the internet using it. It says on my Windows 7 computer that the Vista computer isn't connected to the internet (which it is, and tested), and it comes up with a Yellow Explanation Mark on the Network icon in the System Tray.

The below image shows what I am trying to acheive:

I am using Microsoft Windows 7 Professional and Microsoft Vista Business.

Thanks,

Ethanw