by default, FUPPES will report to devices its SortCapabilities, and obey SortCriteria requests from devices. So when I view a playlist on my PSX3, FUPPES will display the tracks in the order that the PSX3 asks for, instead of the order in the actual playlist.
there is a wishlist item asking for a feature to maintain playlist order. I coded up the "no-sorting" option, which, when enabled, keeps playlists' contents in order, regardless of what the client device asks for. no-sorting lives in the .cfg file and when enabled, FUPPES will not perform any sorting during UPnP browse or search.
unfortunately, I can't get FUPPES and its dependencies to build reasonably on my own system, so I can't test that the change works correctly. I'm happy to provide the code changes for testing/integration, but I don't have svn or tools to create a diff, so if the maintainer is interested in accepting this change, I can supply the changed files (vs SVN 660). I know it's a pain, but since it's something on the wishlist, I figured it might be something the mainstream FUPPES maintainer(s) would be interested in. Let me know.