Internet connection on RAS

We have a remote user calling into our NT RAS server via dial up. He wants to be able to access the internet via his high-speed cable line at the same time as being logged on to RAS. Whenever he calls up Netscape, the browser runs on dial up out to the server’s firewall. How can he run he configure his Netscape browser to always run at high speed cable connection even though he may be running dial up on RAS?
Thanks.