Domain Controller behind NAT

hi,
I am Trying to setup two PCs in a Car to join a Domain and it is not Working. I have the following Setup:

The Setup:
The Car is equipped with router that has Wifi and 3G on one side and Ethernet on the other.
It builds a car-local Lan (192.168.0.0/24) and acts as DHCP, DNS, Router on this lan. The Car-PCs(Win 7 Pro) are connected to this side.
The other side of the router will connect to my "home" Wifi when home and to the 3G network when not.

The Home network (10.65.17.0/24) has a Domain Controller (10.65.17.100, Win 2k3) and 5 Clients. It also has a Wifi AP that bridges the network to the air.

What works:
When I connect a laptop directly to the Wifi it can connect to the Domain and login.
The Car-PCs can access PCs on the Home Network (for example the SMB share on the DC) when the car is in WiFi. So routing from Car-Network to Home-Network works.

What is the goal:
I Want to connect the Car-PCs to the domain so I can manage them from my DC. When the are "at home" the login should be against the DC. When They are not "at home" they can obviously not connect to the DC but the logins should be cached and one should be able to login to the PCs.

What is the problem:
I Can not connect the Car-PCs to the domain. When I Try they send a SMB message to 192.168.0.255 to find the DC. This Does not work because in 192.168.0.255 is no DC, its on 10.65.17.100 and the router does not translate broadcast messages(and that is correct behavior).

Possible Sollutions and why they are not working:
I could set up the Car-Router as Bridge mode. This would obviously work because all clients would be in the same network and Broadcasting would no longer be a problem. This would however imply that the "home-network"-DHCP would also provide the IP-Addresses for the Car-PCs. But If I move out of the Wifi this Server is gone and that would render the whole Car-network useless.

My Questions:
Is there a way to manually specify the DC IP-Address?
Do you have any other Idea on solving this problem?

Thank you for your Answers.
Best regards
Clemens

I think that for home network you wont be requiring the need of a domain. Make workgroup instead (my computer-properties-network ID) and give any name which should be same on both the systems. Then go to control panel and run "network setup wizard" on both the pc, and all will be done, hope that helps you out.