Time Machine + Time Capsule + Wireless router = Frustration

[Don0344]

I purchased a Time Capsule from an Apple Store about two months ago. It seemed like a good idea, actually an excellent idea, at the time. I have a MBP core 2 duo. I connect to the Internet with a Verizon USB 727 wireless modem that is plugged in to a USB port on the MBP. The Internet connection works great. When I set up Time Capsule (and I have done this many times) I get an error message that says that there is nothing connected to the Ethernet port - and tells me to connect my router to this port. I do not have a router with an ethernet port. My modem is wireless. The "Air" in Airport seems to indicate that it is a wireless device but somehow Airport insists that I connect a wired router to it. I can eventually get everything to work and connect other devices to the Internet via the Airport but every time I shut my system down I have to jump through hoops to get it restarted - i.e. run the airport utility and re-establish Time Capsule as my Time Machine backup drive. I have updated all software including Airport Utility (version 5.5). Is this just something I have to live with or should my Time Capsule be able to handle a wireless modem?

Sorry to be so wordy but I wanted to explain thoroughly. Thanks for any help.

Don