As there have been several questions I'll attempt to answer them in this post in order.

Remote User: And you didn't put this info in the Wiki because.... ? ? ?
I've never entered content in a Wiki and didn't even think about it. Given the number of questions I'll probably try to explain things a little better before I try putting it in.

hobbes: what hub are you using?
A Cyberpower 4-port USB 2.0 powered hub. $20 at Walmart and very easy to modify since it snaps apart without screws.

tonberry1: Mm, so no external hub needed?
Yes and no :-) It can work without a hub or with a powered hub. I have added batteries and can use it without a hub as it will supply the necessary 5 volts to the 770 to let it know a USB device is plugged in as well as powering the keyboard. It's a bit neater that chopping cables up to hook up power. I disconnect the batteries when plugging it into the hub. People are going the modified cable route so they can plug in other devices besides a keyboard. In my case I've now modified a hub to supply power to the 770 so there's no need for cable modifications.

daf: Ok, i understand what you say, with an hack, you can use this keyboard with battery. So this keyboard is not a working USB Peripheral because it does not work without modifications.
See my previous answer-- it works without modifications with a powered hub. It was just more fun to avoid modifying cables.