The DO may not be empty at initial, because user may has written something before.

From TrueCrypt view, when user choose to import a file to token, TrueCrypt will create a new file, instead of replacing existing one.
If there is already 1 file, TrueCrypt will add 2nd file. So, if the DO is empty, we will show nothing, and when user import file, he will see 1 new file in the list. If DO has data already, we show it, and user need to delete before writing.