Hi Bryan, I've run into a snag right off the bat. I signed in and went to the Create a Custom Export Format link. I gave the export a name and description and saved it. Once I do that, the name and description default back to "untitled", and when I go back to "Your Files", I'm left with two exports, both labeled "Untitled".
I tried this with both Firefox 4 beta 6, and Internet Exploder 8.