MP3 Export does not provide a way to set copyright info

MP3 files have some standard fields in them for indicating the composer's name, the title of the piece, etc. While many music programs provide a way of setting this info, MuseScore's export function does not. It would be useful to allow the user to specify this meta information so it is exported along with the .mp3 file. It would also be helpful if Musescore could retain this info so that the user does not have to reenter it every time they export their file.