I don't think Subsonic handles your files the way you want it.
Subsonic converts all audio files into a "streamable" format like mp3. It doesn't check wether the client can play any format, it just presents the mediafiles as a stream.
If the program to play your dsf-files can handle DLNA than you might enable Subsonic's DNLA service and let the client find the files this way.
Subsonic can't handle PDF-files. It just does imagefiles for Covertart. JPG, PNG, GIF. etc.
You might have a look at
http://www.computeraudiophile.com/f11-software/dsf-flac-help-20429/ whether it's an option to convert your files to Flac.
That format Subsonic can handle without any difficulty.