This'll probably be no use whatsoever (I'm world class at that sort of advice) but I went to have a look on the Beemer and there was an option to 'import files' on the memory stick screen in the car and when I did that, all the 'hidden files' on the stick appeared. I assume imported to the car's own hard drive. I don't have folders though, the car just shows everything under options of albums, songs or artists. It's sorted me out though. I celebrated with a quick blast of Can Utility and the Coastliners.