NewIT talk about power the plug via a powered usb hub , but not heard of powering the plug via the ethernet cable when you haven`t got a power over ethernet router connected .
Is it coming via the Esata port ?
Not got anything hooked up to esata at the moment. I did a little test - it will work if I leave either the USB hub (powered) connected, or if I leave the ethernet connected. With ethernet I tested it plugged into a cheap £10 10/100 switch as well as plugged into a homeplug and then finally my Mac Pro. It worked on all of them!