Snow Leopard Server 10.6 VPN and Ask4 Internet

Hi i currently live in halls and I was wondering if anyone has managed to get VPN to work with Internet browsing on a Ask4 Internet connection? As have managed to setup VPN and can connect to it locally but unable to browse the Internet. I have used different configurations such as setting a private ip and mask in the routing table but still no joy. Do i need to setup DNS and DHCP to get this to work?

Thanks in advance.