I have Verizon, but I have a Treo 650. Apparently Treos in general have trouble transferring their phone books to the Camry, regardless of the carrier. Anyhow, I just use voice dial as follows:

1) Press the Talk button.

2) Say "Dial by Number."

3) Wait for prompting and press the Talk button again.

4) Say the number and confirm that it is correct (if not press Talk and say GO BACK, and do it again)

5) If the number is correct press the Off Hook button and it dials.

In most cases the numbers I would be calling from my car are numbers I know without looking them up anyway, so for me it doesn't matter that much.