I found a solution. I use the Universal Media Server (an embellishment of the Playstation Media Server -
http://www.universalmediaserver.com/) to stream movies, photos, and music to my PS3, and I found that it shows up and runs on the M500. Moreover the UMS has a setting that lets it read and serve iTunes, including playlists, and this runs perfectly on the M500. So squeezed a little more life out of these wheezy gadgets.