Wifi sync blank in IOS 6...

Hi

I have an iPhone 5. After "downgrading" from IOS 5 to IOS 6 I have lost my wifi sync, as you can see, the option is not even there...

1/ I have it selected on in Itunes 11

2/ I have a 2012 IMac with Mountain Lion fully updated.

3/ I have a stock standard 2012 Airport Extreme with out of the box settings

I can see the phone in iTunes but if I deselect, sync and then reselect "Sync this iphone over Wifi" it has no effect.

Does anyone have any ideas to get it working again.