Internet sharing on Ad Hoc Network

[syansbahrisunsea]

Hi ,
I need anybody's help

I have a problem on sharing the internet connection on adhoc LAN
I and my neighbour both have laptop with Vista Ultimate connected through Built-in WiFi device
I'm using a Portable USB modem for my dial-up connection

both laptops are connected locally
the host laptop can connect to internet, but the second laptop just stacks on local network and cannot access the internet.

I've many times and ways to configur the internet sharing, I've tried using ICS, setting the IP address, and when I do a ping, it indicates that the laptops are communicating one another,

If I lookup to the device in the network and sharing center, the devise is shared.
what could be the solution?

please!