Apple is not part of DLNA league. Itunes is not a compatible streaming client for Sony (or pretty much anyone else). You will need to have Win Media Player sitting in background to do it, or install something like TVersity etc....
However, you can forget your playlists. TVersity picks them up erratically, and WinMP wont see them at all (unless you manually keep them synched).
Unless you HAVE to have iTunes, then ditch it and stick with Win Media Player. Its far more compatible and both the encoding and sound quality are better. If you dont believe me try it for yourself.