Ever since I installed Xubuntu Natty, my mp3 player is not mounted any more.
lsusb also does not list it. Normal USB sticks are normally mounted. How can I re-enable auto-mount for it or mount it manually?
This is a known bug #763227 which you can read on Launchpad here.
If you update your kernel to 2.6.38-10 or above it should fix the problem.