The media server (Twonky) uses the metadata tags in the files to present file information to DLNA clients like WMP or your Pioneer. So, if you want Twonky to present accurate track information, you will have to add metadata tags to them. You can usually do this automatically with a media library manager, like MediaMonkey, or a specialist tagger like MP3Tag.
Even then, the way in which tracks are presented on the DLNA client varies from client to client; see this thread for examples:
