thats odd ax! Weird that they would work on the 120 and not the new drive. I'm sure you have but I thought I'd ask anyway. Have you tried a second time to get the emus to work?
Just trying to make sence of this cause the size of the drive should not matter at all, so it does lead one to believe maybe you missed something. Not that emus are that difficult and you do know your way around the xbox pretty well. I'm no expert by any means on the Xbox aspect of it but it would be about the same as a pc. In that regard, it should be working.

I know I may not be much help but it does make you rethink your previous attempt(s) just to be sure.