HTC Sensation connects but now Prius won't tell me who's calling

I changed to an HTC Sensation and connected it to my car. Now when people call the car never has their name pop up on the screen like it did with my old phone. I realized it's because for some reason this phone adds a 1 before every number so since the number the contact is calling from doesn't match the one listed in the car that's why it won't show up. This phone does not appear to allow me to turn off the country code either. I tried replacing the phone book in the car with the one in my phone but I don't have my contacts saved with a 1 in front. Is there a way to add a 1 to all of the contacts in my car? Or does anyone know how to turn off the country codes on the HTC Sensation? I've emailed HTC but the response I received was very generic and was only in reference to roaming. Any help would be greatly appreciated.

Thanks