Sounds like op wants to install hb by putting hackmii on a usb stick. Its not possible.you can load apps from usb if you have hc installed already. If your trying to install it from usb... I don't know.[I hate telling people "no, you can't do this or that."]
(loading apps from the usb is worse than doing it from sd but it still works. Just a little frustrating.)
You are corret saying you can load apps from usb hdd but only after the mod.