Well, it looks like I'm a bit out of luck right now.
I found some more info on other forums that suggest that my problem is due to the German firmware.
As I mentioned, my problem is that Bluetooth Assistant thinks the phone doesn't have ANY services. So, it's assuming it can't sync, transfer files, etc. Other people have mentioned this problem with phones purchased off eBay that come with German firmware.
It sounds like I need to update my phone with US firmware, in order to solve this problem. Of course, the required software is Windows-only, as well as being nearly impossible to find... (not available to the general public).
I keep telling myself that, at least I saved some money and didn't have to lock myself into another 2 years with Cingular...