Finally, I’ve managed to copy files on the device by simulating drag’n'drop on the virtual folders created by VFSWrapper. This VFSWrapper *has* a COM interface, but totally unusable (although good function and parameter names, I couldn’t get it to work). Nokia Multimedia Converter is in the same situation, COM interface but no way to get it work. We may resign to use some 3GP codecs, if we find some. In the end, the good news is that some non-Symbian, Series 40 phones may be compatible with our solution as well (6230 seems to mount its filesystem also, for example).