Although I eventually met up with the same level of success it was not nearly as easy. But with a bit of effort, and a very helpful local repair outfit I am finally up and running.
I called last night and tried to get them to do as you have listed and I unfortunately did not get the same guy. After four more hours I not only could not tether but she so screwed up my provisioning that none of my data services worked. She said it was the phone and to go in and have it replaced. So the adventure began again this AM. I went in and did just that, same issues. Spent another two hours on the phone. For what it is worth I may have talked to the guy you had, as this guy was all there. He tried all kinds of stuff to no avail, but he really knew what he was doing. He finally gave up and tried to transfer me to "advanced technical services" what a misnomer that is. In short I went from there, to somewhere in NY who worked with Enterprise and she was as clueless as you can get. Then I went to the Phillipines to some guy that told me my phone number had been ported properly (no duh that happened two weeks ago!) then I was sent right back where I started only this guy was new to blackberry's. Luckily the call got dropped when he was trying to send me to the "blackberry expert".
So now for the good part. I took it back and told them to keep it and they told me to try the local repair shop as a last resort. Why, not I had so much in this already and I would have to call another person to send it back. Well, two hours later it turns out everything was "almost right" he located some "stall code" that somehow had been entered on my account". It was cleared and bingo it worked. I took it home and restored it so I had all my settings, hooked it up to the PC and it worked first time. Just hooked it up to the Mac, and again, it hooked right up. It tethers perfectly now. Different guy, but he too saved a customer. He was fantastic to work with and is getting the same letter. With all the pain I will say that they were all very pleasant to deal with in my case. Few really had a clue about this phone, and the issues with it, but they were all pleasant. Now I can finally get back to making money as opposed to wasting my time on the phone!!