I, and TWC, couldn't figure out how to make the Ubee modem behave with my network which starts with a TC. My Motorola modem failed and they replaced it with a Ubee.
Initially, the tech wanted me to put the TC in bridge mode. I didn't want to do that. I want the TWC device to work with my network and not the other way around. Going to bridge mode breaks part of network and I didn't want to take the time to fix it. And its bad for my Slingbox, among other devices.
The Ubee menu doesn't allow you to disable NAT and it didn't seem like the radio disable really worked. I would disable the primary network but still see the SSID of the box. Disabling the DHCP server doesn't disable NAT and in fact makes the modem unable to talk to anything. I had to reset the thing a couple times just to get back into it. And its big. I'm sure a gateway is great for some people but if you have a pre-exhisting network then it is a headache and a half.
So I called back and said bring me back the Motorola. Plugged it in. Disabled the primary network, NAPT, turned off IP flood, and restarted it. Everything took, everything worked, everything visible when I tunnel in...happy SigHome customer. But the Ubee modem is now banned from my house.