Alright... of course all warnings etc. from the initial post apply as well I connect the whole shebang via USB. Though I am not using the USB port but rather the pads beneath the battery (see the first image). I took the Powermat receiver of an Iphone 3G Powermat set. You can pretty easily break it off the casing without damaging it. Furthermore, it is internally connected via a flat ribbon cable which detaches easily. On the second picture you can see where I identified GND and +5V (actually you get something around 5.2V from it). I accidentally fried the first GND soldering pad located next to the +5V pad so I used another GND pad which can be seen in the background.