ISA 2004 as VPN server

[mdaoud]

hi all
i have win 2003 with isa 2004 firewall, i enabled vpn in isa server and make access rule that allow from VPN clients to internal and local host all protocol, all user and i add my user name to vpn group in active directory, now when i connect from my XP client i receive private IP (192.168.1.x)and i can ping and access local host(isa server) but i cant ping or access any resource behaind isa firewall like file server
please help