After the failure of my cable TV/Internet service last month, and the slow response of the cable company, I dumped cable in favor of satellite+DSL. It was an inconvenient process to say the least. When it was done, I needed to connect the satellite DVR to the wireless DSL router to enable additional features.
The DVR had a USB wireless adapter, but because of the location of router, the signal was not quite strong enough to make the connection work. I had a spare Airport Express and my first thought was to use it to extend the DSL router network. Before doing any research, I made manual changes to the Airport Express that rendered it a brick. Doh!
I found a helpful article at Apple Support that let me reset it to factory settings. Then, I finally did the research and found that the plain Express can't be used to extend a 2WIRE wireless router.
The next strategy was to set up a separate wireless network and plug the Airport Express into one of the wired ports on the router. The Airport Express provided a stronger signal that the 2WIRE and allowed me to connect the DVR to the Internet. The only modification I had to make from a basic configuration was to turn off network address translation (NAT) on the Airport Express to avoid a double NAT situation since the 2WIRE also provided NAT. The Airport Express actually detected the problem and made the suggestion when I connected to it with the Airport Utility. Apple really has some very nicely thought out software in their hardware.