It eventually worked. I signed up for the monthly thing, and tried to load pages, and it would continually ask for activation again and again say that it couldn't find my device. So I powered it off, waited a few minutes, and turned it back on. I manually connected it to XOHM and it did the all-important "Updating WiMax settings" and then it worked! I guess it needs to do the updating settings, but I'm not sure how to force it to do so without disconnecting and reconnecting.