Well, i popped open the belkin pack a couple of weeks ago, its not that hard:
with the battery cover off, on each side of the pack, there are two "rails" that the cover slides on. take one, press it inwards and pull up. now, instead of going to the other side, move across to the front of the pack, and pry it some more. this should give more clearance on the side you just yanked up, so it is no longer hooked onto the rest of the pack. no just lift out the other side. upon looking inside the pack, youll notice a certain lack of electronics. thats because this pack costs only about $6 for the materials to build it. Its a very simple piece of electronics, and in my opinion not worth it at all for 50-60 dollars. If you'll look there are two places where the electronics are soldered on. the front where the leds, and the pack where the firewire cable is. the board where the firewire cable is attached is where the mysterious gizmo that makes it run off of only 6 volts resides. right in the middle youll notice a chip, and i thinks thats the "step up inverter" or something like that. thats what makes the whole thing work
i hope ive helped you, even though i havent answered your question about the power connectors.