Windows Server 2003 RRAS Issue

This is a long message, so stay with me

All -

I'm attempting to implement a solution for a client, and I'm having some rather annoying problems with it. What the client desires is the following. For their remote sites, they want a server to be configured as a Demand Dial Router as a backup for their Cisco router/WAN connection. Should the WAN connection fail, or the router die, they want all traffic to automatically be routed to the server, and the server will then establish a DDR session with their main office's RRAS server. In summary:
1- When the WAN connection is functioning properly, the server and all clients should be sending packets to the Cisco router for proper routing over the WAN.
2- When the WAN connection is not available (Sprint routing issue/fibre cut/etc) but the router is up, all clients should send packets to the router, and the router should send them to the server. The server should dial into the main office and route traffic over the DDR connection.
3- When the ROUTER is not available (router hardware failure), all clients should send packets directly to the server, and the server should dial into the main office and route traffic.

OK, so that describes the requirements. Now on to the problem. I've worked just about everything out except for one thing. I can get the client PCs to have two routes for 0.0.0.0/0.0.0.0, with the lower-weight route pointing to the router, and the higher-weight route pointing to the server (which solves requirement #3). I can get the router to spew packets back to the server and have the server route them over the DDR connection (which solves requirement #2).

What I can't do is have the server have a default route for 0.0.0.0/0.0.0.0 for the router AND have a second default route of 0.0.0.0/0.0.0.0 for the DDR connection. As soon as I add the DDR route in the RRAS management console, all routing for anything that doesn't have an explicit route fails.

The routes SHOULD look something like this:
Dest       Mask       Gateway     Interface      Metric
0.0.0.0    0.0.0.0    10.10.1.1   10.10.30.134   20
0.0.0.0    0.0.0.0    (DDR IP)    (DDR IP)       30

Instead, IT ends up looking like this:
Dest       Mask       Gateway     Interface      Metric
0.0.0.0    0.0.0.0    0.0.0.0     ffffffffff     30

If I manually remove the default route to the router and add the static route to the DDR, DDR works fine. If I remove the static route to the DDR and have just the default route to the router, that works fine as well. It's when I have both in that causes the problem.

Having a redundant route for 0.0.0.0/0.0.0.0 works fine on other systems, as long as there is a defined gateway and interface.

Has anyone seen this before? Can anyone lend some assistance?

FWIW, I'm running Windows Server 2003 Standard, and I have plenty of processor, disk, and memory.