That information is passed to the 500 as an ordered collection if the books are in the main memory. On the 505 it works for all books.
I'm not inclined to implement this, as the internal modular architecture of libprs500 means that the module that passes metadata to the device isn't aware of the type of device. Since this feature is really only useful on the 500 for books on SD cards, it seems that re-architecting libprs500 is too much work for suh a limited use case
