I'm in Los Angeles and I need to get the SIM for the Nextel 7510. I've been told by Nextel that the BB SIM is gray. I have the yellow 64K SIM from Motorola. BUT here's the catch....the Nextel Service Center will not service the unit unless it has the gray SIM. I can't add it to my account unles I have that card in it. WHERE CAN I GET A SIM for the BB?