I'm not 100% sure but I don't think it will work 'cause the 7.0.x software will only support IPSEC tunnels and in the native XP settings I haven't found a way to specify the tunnel group.
It works of course fine with the Cisco 4.6 VPN client but that messes up your standard XP VPN's unless you set the Cisco firewall service to manual and start it before you Cisco VPN into your PIX and stop it when you are through...
