Problems using RRAS Nat with VPN using RDP

Hey,

I am trying to connect from home either using RDP or tightvnc. Neither of which is working.
Here is the network background:

ethernet -----> firewall (checkpoint) ---> MS domain controller ( 2 interfaces) --> external ethernet and internal private network ( 10.10.10.0).

I can access the domain controller using RDP if I use the external address. I want to be able to RDP/VNC to the private network without going(RDP) through the domain controller. Can I do this? What do I have to setup on the domain controller?

With wireshark I can see that the VPN translation is working and I get to the DC, but I don't get anything in return.

I have RRAS Nat setup and have the RDP/VNC ports setup in the nat but I don't get anything on the private network.

Anyone have an answer/ idea?

thanks