Dialup ISP problems on laptops

Trying to set up a dialup connection for a laptop for a user on the move (windows xp).

Whilst at work, internet access is through the LAN via a compulsary proxy server. I’ve set up a free dialup ISP. When attempting to use the ISP (away from network), it can’t find a route through to internet because it’s trying to find the proxy.

The user of the laptop has W2K policies in force so restrictions apply. The user can’t disable the proxy each time he’s away from the office because he doesn’t have access rights – it needs to be automated. Any assistance would be appreciated. Thanks!