I have a Motorola NVG510 modem from AT&T, and I would like to disable all routing functions and use it as just a modem. I have a Time Capsule that's already connected and broadcasting its own wireless network, which is how I've been connecting (it's been reporting a double-NAT error, which I assume is from the NVG510 also acting as a router).

I followed the instructions in question six here, and I can connect as I did before, but my Time Capsule still has a double-NAT error.

How do I put the NVG510 into bridge mode or otherwise fix the double-NAT error? (No, ignoring it does not count as a fix.)