I don't know if this makes any difference or applies at all, but we used (still do just for voice plans) ATTWS. I was part of a pilot group evaluating BBs which we got from Cingular. When the unit arrived, shipped directly from Cingular, the box had a label with my name and cell phone number on it. When I activated the unit with the SIM that cam in it, I got an Invalid SIM error message. I then removed the SIM from my ATTWS phone, installed it in the Cingular BB and it has worked great. We did have to provide our BB admin with the serial number of the SIM before we recieved the units. Maybe the difference is we are a nationwide business account? Or SIMs in phones not locked like they are in BBs?