I have the v710 also - ugh! If you're not aware of the class action suit regarding the hobbling of the v710's bluetooth capabilities (which cause problems like the one you're reporting), and you're a California resident, you might take a look here:
http://www.kirtlandpackard.com/v710/
The only options for setting up your address book that I'm aware of are:
1. to load the number from a list of recent calls in the Prius database (which I can't remember how to do offhand, but it's not that great a solution being that it only stores the phone number and not the name (and when the car is in motion it will hide the phone number, leaving you with your memory of which quick-dial button to push)
2. to have a friend with a bluetooth phone put your address book on his phone and upload the addresses to your Prius.
Wish I knew of a better solution!
