The TVersity UPnP Media Server supports m3u and pls playlists where all you need to do with TVersity is share the folder where your playlists are stored and then when you search the Media Tree i.e. Audio - My Audio - Playlists using Media Streamer you should be good to go. Here is an example of very simple m3u playlist stored in My Music folder which I have just tested playback with Media Streamer :-
Playlists can be created/manipulated by almost all PC Media Players i.e. Winamp, WMP where you can usually specify the format of your saved playlist very easily etc.

TIP: with Media streamer if you select a UPnP server served playlist folder but do not open it, then add the folder to the Media Streamer playlist ALL tracks within the playlist folder are added to the "on the fly" Media Streamer playlist where it can be further manipulated using the Media streamer promote/demote track option for example.

This way numerous prepared playlists created/stored in your master music storage area are always available for merging and manipulating on the fly (This is my understanding anyway)

I agree that saving the playlist is what we ultimately need but then we will want to save locally on the Nokia 770 and remotely in our central music store.