@Domino1999: Yes it has. I tested it with my company's laptop (a Dell Latitude E6410) with Windows XP installed and the Mede8er now is recognized. I see actually an external hard drive (there is no folder structure though). So the problem is the Sony FGN-FW31J with Windows 7 32bits installed. A pity I cannot use my company's laptop to download mega-sized files.
Update: I also have connected it to my selve-made PC with Windows 7 Ultimate 64bits. It recognizes the Mede8er as "File-backed Storage Gadget" and Windows shows a drive-letter with name "Lokale Schijf" (Local Disk). When I try to view it, the Windows Explorer kind of freezes. It just sticks on the drive it was before, but does not select the Mede8er's drive-letter. When I close the Windows Explorer, it freezes completely.

Update2: I connected it to another USB-slot of my PC and now I can copy the files to the Mede8er

However, the problem with the Sony FGN-FW31J still is actual
