Generally, the same issue with not being able to charge from either AC outlet or from my MBA AND Iphone5 not being discovered by Itunes ( also on Windows 7 machines). But for reasons unknow ( supposedly to apple tech support as well), charging and sync with Itunes has been erratically (on and off with out obvious reasons) possible !
Went to Apple store today( with my case number and an appointment) and was told to swap the iphone5 with a new one but not the usb cable and power dock. Charging, syn and setting up backup went fine but now, again, i am not able to charge the phone and Itunes does not recognize it as a new device.
Would be good to know if this problem fo charging and sync with Itunes has persisted after getting new power cords or a new phone. Thanks !