seting up win2000 server for vpn

Please help! My company is trying to
setup a VPN network with our plant in
Mexico. We are in testing phase of the project trying to establish a VPN correction. We are using a Win2000 server, 3Com Lan modem at both ends. Using a single ISP for the testing phase. My problem is: I am not certain on of the correct RAS settings for the win2000 server or the lan modems. I have a static IP address from the ISP, IP address for the Lan modems, the server has 3 network cards each with their own IP’s address, and the win2000 work stations have the own IP addresses as well. How do I map the path with these IP’s in RAS?
Thanks