Oh snap! I Just tried it and it's working!!
What you need to do is go into diagnostics mode or w/e it's called, put the Wiikey 1.9g disc in and boot it, after the update is done, eject the disc and place Brawl in, and then reboot in diagnostics mode!
Seriously... no offence but this video doesn't prove too much, except for the fact that the Japanese game can't be played on an NTSC-U machine. I mean come on now...
Oh and.... POW RIGHT IN THE KISSER!!! LOLWTFBBQ?
Ok I'm done.
Joke? Do you have the game? Not trying to take away your credibility...just asking. How do you go into diagnostics mode?