How to associate a file extension to a card directory

When you try to sync a file to the expansion card, often, you got an error saing that there is not a program associated to that file type

// For example to unregister the .txt extension write this
VFSUnregisterDefaultDirectory(".txt", expMediaType_Any);

// To associate the .txt extension to the /PALM/Laungher directory use this
VFSRegisterDefaultDirectory(".txt", expMediaType_Any, "/PALM/Launcher");