As has been mentioned, the four pin firewire connection will not power your back.
If you are in a studio environment, or anywhere where you have access to electricity, then use the expresscard as shown in the third link in the post above. With no problems whatsoever, I've been powering and connecting my phase one back to a sony vaio, and before that to an acer notebook, through a firewire expresscard. Shooting directly into capture one, I see no hugely significant delay to shooting into my desktop in the studio. And if you're shooting multishot, then I imagine the time it takes to transfer into the notebook with the expresscard is irrelevant.
regards
Stefan