the fdisk command i gave you could read the partition table fine.
(it didnt register them, just print)

the code thats handling the automounting (/shr) should'v discovered
the partitions by running the same command but apparently that didnt
work. (otherwise, the dos partition should'v shown up in /dev/sdU*)

i can not reproduce this on my systems and i need further information
to debug this issue.

i would like you to:

  pulling and replugging the usb device and watch the screen to see
  if there are messages showing up. (you can also run cat /dev/kprint in a rio
  window to capture the console output (make sure to make the window
  scrolling))

  try a different dos formatted usb drive.

--
cinap