Help with ipod battery charger!?

I am making an external battery charger for my ipod touch. This involves 4 AA batteries being fed to the +5VDC pin of a usb port and the - pin. Now i have a circuit that gives power. Ipod touch requires data communication to initialize charging so i've fed two resistors going to D+ and D- of 560k ohm which gives me a voltage of 2.2v. Charging is now initialized. However, the voltage reading of my 4 AA batteries is 5.1v when ipod is not plugged in and 4.1 when it is plugged in. The ipod isn't actually charging even though it say it is…Surely it should be 6v and seeing as the resistors are in parallel it should have no effect. I really do not understand this…

http://i29.tinypic.com/ajr0gy.jpg
I can confirm that it is the circuit as i cut a usb cable and used the 5v from the usb port as my power source and charging initializes but it doesn't charge. I really don't understand this now…The resistors are in parallel please either answer or email me at cus@cus.me.uk