Unable to create playlist for external memory

I am having a similar issue.  I am trying to create a playlist accessing songs from both internal and external memory, by creating a .pla file with Windows Explorer (see link)

http://forums.sandisk.com/t5/Clip-Zip/Sansa-Clip-Zip-is-changing-my-playlists-zapping-external-memory/td-p/264153

When I disconnect the USB, everything is fine - it plays from both internal and external memory.  But if I reconnect via USB and just look at the .pla file, all the references to the external memory songs are gone (the internal memory songs are still there). Actually, I can connect via USB and the playlist remains intact as long as I don’t navigate to it in Windows Explorer (i.e., I can connect to recharge).

The SanDisk support team suggest I reformat the Clip Zip, reload the 01.01.18 firmware and all my songs, but that sounds a bit drastic.

It just seems odd that just navigating to the .pla files corrupts them, no matter where I save them.  I made several copies that I thought would be “backups”, but they all get zapped.  And I was hoping I could save the .pla somewhere on the computer, but apparently that doesn’t work either.

(btw, I connect in MTP mode)

Any recommendations?