I want to thank Balding Parrot for this tutorial. I've been using and learning BT3b for a month or so and have neglected to say thanks.
If you follow the instructions carefully and add "changes" per PureH@tes note it will work.
I used acronis in windows for the partitioning, a WD usb hd, on a Toshiba U305-s5077.
I just added a powered usb hub to plug the WD into. Now the usb boot choice comes up every time. I think about a dual boot install, but this works too well