I actually beat that fucker, I pretty much did everything in final fantasy 9,
the thing is that it takes a shitload of luck to be honest, keep using dark matters which would do about 9999 damage if I'm not wrong, that and all the abilities to steiner and freya which kicks ass too.
the boss itself doesn't have much more hp than 60k if I'm not wrong
anyway here's a link
http://technorati.com/videos/youtube.co ... HM7kgvbr2E
I noticed that they use return magic a lot in it, might be an idea
edit : it is possible to defeat this boss with almost any setup, so just take your highest level people and get in there and do some damage quickly, speed is the factor