Thanks for the information. I checked with Sprint and I can't add the ext. on to the numberI have a 2008 535 and the car automatically uploads the phone numbers and extentions programmed into my cell phone when connected by bluetooth.
My problem is when I use the blue tooth, because I can't put the ext on to the phone # I have to wait until the connection is made then punch the ext # in on the cell phone.You will have to insert "P" pause on your cell phone and type the extension that prompts the phone to let the number ring then dial extension. That is the same way I use for my voicemail P then type in your password so you don't have to type in your password everytime you call voicemail.