If you pull the playlist URL periodically, and located it in an auto-import directory, perhaps this will work?
I'm just wondering (and what I wanted to test) if it'd work if you add the "playlist" a different way...
You can also add it by:
1. Go to Audio > Connected Media in the tree.
2. Right click on Connected Media and choose Add Website.
3. Enter a name and the URL of the feed.
4. Hit OK. Now you have an entry under Connected Media that points to the playlist. This should use not the contents of the playlist, but the dynamic playlist URL itself (pulling the contents whenever you "play" it).
(See attached screenshot.)
The thing I
don't know is if the Connected Media items are shared by the Library Server, so that they're accessible on the Client-end, because I haven't used them much. It also might not work if you want to access them from a DLNA client or something (though I'm pretty sure you can get to them from Theater View, so you should be able to add them to the Media Network system too, I think)...