Search the web for "gnome-volume-manager". The community of one of the
other WMs I mentioned (though I can't remember which off the top of my head)
favors Rox as a file manager, which reportedly provides the same
convenience. When I have a moment to do so, I will run gnome-volume-manager
under Fluxbox, perhaps at startup, and see if automount starts to work. I
noticed that my (sound) volume buttons work when I run the Gnome component
for governing sound functions.