Stupid Apple (Sorry, they're not stupid. I'm just mad) didn't impliment that feature into OS X yet. The reason that it shows in OS 9 is because it's still assigning the icon to the drive. OS X just hasn't been programmed to SHOW the custom icon yet.
I have a feeling that'll be fixed in X.1... Atleast it'd BETTER be.
As much as I'm hoping, I have small feeling that OS X.1 won't be delivered at MacWorld NY. That makes me sad. I want it soooooooooooooo badly. Also, I DON'T want to pay anything for it.. I already paid $119 for X.0.. Why should I have to pay more for an update that should have been in the FIRST release?