OK - so I finally got it figured out. All it took was a call to T-Mobile that went on for almost 40 minutes, before they realized it was an issue for RIM. Another long wait and then we had to disconnect because RIM was not responding (or something) and I had to go home. Then this morning it was only another interminable call and waiting and it went on for almost 2 hours. Of course, the very last thing the RIM tech guy suggested was the one that worked. After uninstalling, reinstaling, editing the registry, deleting RIM folders and files on the C drive, he walked me through changing the profile. Then, using the new profile, I set up the synch and it worked like a charm.
Thank goodness. I was ready to pitch my Bb into the nearest lake or mountain gorge or dumpster.
Thanks, RIM tech guy, for your patience, persistence and overall great assistance.