How to solve problem with w2k3 + vpn client + rdp?

Question

VPN

There are windows 2003 behind nat.
Port 3389 is forwarded to it from the rdp router.
Everything works with a bang, but there was a need to raise a vpn client on the server and let all the traffic through it.
Raised openvpn / pptp (tried it this way and that) when connecting and replacing the default gateway, it breaks all connections to the north via rdp and does not let new ones. On the vpn side of the server is debian linux.
The same configuration works on windows 7, it does not break connections, it allows rdp, tell me which way to dig?
I tried to register both persistent route and just routes, but it seems that he ignores everything.
Windows firewall disabled / enabled and added exceptions - did not help.