i believe sync n backup are two different processes.
unlike the other phone manufacturers, apple doesnt allow us to set actually the direction of sync.( ie phone to pc, pc to phone, etc)
even after authorizing a new pc, and when i connect the phone, i find my grid views change and i have to manually drop back the application to my phone.
secondly, the direction of the contacts isnt clear.
if it had an option for backing up all the contents into a file, it would have been easier to restore them according to one's choice...cos this sync is so unpredictable.