Being aware that this phone is basically a Series 60 device, I searched the web and find an easy hack, on how to get things working. Credits go to http://laiwebdejuan.50webs.com.

Here how it goes:

You will need to fake your phone as a 6131 to the iSync software:

• Open a Finder window, then right clink on iSync’s package on the Applications folder and select “Show Package Contents“;
• Then go to the folder: Contents/PlugIns/ApplePhoneConduit.syncdevice/Contents/Plugins;
• Right click on the Nokia-6131.phoneplugin file and select “Show Package Contents”;
• Then go to the folder: Contents/Resources and edit the file MetaClasses.plist with TextEdit;
• Search and replace for all “6131″ occurrences for “5200″ and that is it.

He also pointed that you can change the icon for the device by putting a .tiff file on that folder: com.nokia.5200.tiff.

Thanks Juan for that tip!