My iPod, which I sync with iSync, has the set of records for both apps that I want to start as the default. I tried deleting all the contacts, and appointments, on the machine, but then when I try to sync it says it wants to wipe them off the iPod. How can I reset these apps so they will think they haven't ever been even launched at all so they'll receive the changess from my mobile devices and use their contents as the master for the first sync?