Playlists on External SD

I have searched the threads here and have been unable to solve this common problem:

I have a 4GB Sansa Clip with an extrernal 16GB microSD. I have roughly 18GB all organized by playlists. I am able to sync playlists on the internal storage without a problem. However, when playlists are sync’d through WMP, the playlist will display on the Clip, but it shows empty.

The songs are on the card, but not tied to the playlist, or vice versa. When I click on the playlists in windows explorer, it shows the playlist as empty, whereas I click on the playlists on the internal storage via windows explorer, it shows the songs linked to that playist.  I have tried it in both USB modes, but the problem remains. I have way too many playlists to create each one manually in explorer. Is there anyway to fix this?

The paths to files are most likely incorrect. If so, there is a way of mass-fixing it.

P.S. You might also want to think about organizing your music by proper tags instead of playlists. Lists are more for compilations etc, and are a bit clumsy for organizing the whole library.