Sony Walkman Playlists + Ubuntu

Hi everyone.

I've got a Sony Walkman S-series, the NWZ-S544 (also a NWZ-E344) I would like to get playlists working on this MP3 player. I have tried using Banshee, Amarok, and Rhythmbox, but none of these programs are allowing a playlist to be copied onto the player. I'm using Ubuntu 11.10 kernel 2.

Playlists do work under Windows using WMP. This player DOES NOT SUPPORT M3U, PLS, or xlms playlist formats. They're using that weird WMP playlist format, whatever that happens to be. Under Rhythmbox, I can see the music on the player and right-click, but the option to "add to playlist" is greyed out. Syncing under Rhythmbox wants to put my entire library onto the player, which obviously will not fit.

I installed the MTP plugins, but now the Walkman won't mount as a USB drive for drag-and-drop operations.

How can I get playlists working on this player? Has anyone had any luck getting this to work?

Thanks!