First install [[https://www.archlinux.org/packages/community/i686/udevil/ | udevil ]], so that autofs gets notified when new usb devices attach.

A few notes:
  * exfat fs is not included in core or ntfs-3g, so install exfat-fuse package on archlinux
  * autofs append "-s" parameter to ntfs-3g and mount.exfat, that broken mounting process, the workaround would be replace these two binaries with bash script, remove "-s" then invoke the real binaries. ([[http://archlinuxarm.org/forum/viewtopic.php?f=53&t=7673|credit]])