Only the latest XBox dashboard update supports 32GB sticks. Maybe you’re not quite up to date?
The XBox can copy more than 255 customs to a stick, but none of the current programs (Modio/Party Buffalo/etc) can.
You are about to leave Rhythm Gaming World and access the external songs DB. While no song or file sold for commercially available videogames is hosted there and only fan generated content is allowed, Rhythm Gaming World has no direct control over the database and no files are hosted here. Alright, we had to made you aware of this, now you can visit the database!