After associating your customer's VPN server and DHCP server, the ninth step in setting up a Windows-based virtual...
private network is configuring the remote clients.
Step 9: Configure your remote clients
To allow a Windows XP client computer to access your private network, you must tell it to use a VPN connection.
Get step-by-step instructions on configuring remote clients.
Get more info on setting up your customer's VPN.