So here is how this story began. Since I usually have more than one Motorola Phone in Bluetooth range, I had changed the phone's name in the Bluetooth setup to Wolf's V551 and temporarily enabled "Find-Me" on the phone.
On the Mac, starting the Bluetooth Setup Agent looked like this:



Sure enough, the device showed up and keys were quickly exchanged.



Now, like I said, I was kind of disappointed, when I saw the following screen, stating the disability to iSync the phone:




Apparently, during the latest firmware upgrade, Motorola had changed the phones id, used during the Bluetooth discovery process, from V551 to V551J.


Let's patch the iSync App to make it aware of the id change.
1.) Control-Click the iSync app and "Duplicate", to a version to go back to in case we mess up.
2.) Control-Click the original iSync app and "Show Package Contents"
3.) Drill down all the way to
/Applications/iSync.app/Contents/PlugIns/ApplePhoneConduit.syncdevice
/Contents/PlugIns/PhoneModelsSync.phoneplugin/Contents/Resources/MetaClasses.plist

Double-Click-ing should open the file in the Properties Editor, where the V551 section is quickly identified.



4.) Change the Model identifier (four times) to V551J and save the MetaClasses.plist
5.) Open iSync and select Devices/Add Devices
6.) YES!




7.) After adjusting some of the default sync setting:




8.) My Mac OS address book and the v551 were in-sync.