HI,
I have one of those USB hard drive cases, and I have my old hard drive in it.
Eventhough I have made the changes to mount multiple USB drives in one USB device (works fine for my media play with internal and SD drive), I am only getting the first partition (/Boot (2)) automounted.
df does not show anything more about the drive, but the gnome hardware browser shows all three partitions on the drive:
/dev/sda sda1 ext3 sda2 linux-swap sda3 LVM Physical Volume
Naturally it is sda3 that I want to access.
I used the following to figure it out. http://tldp.org/HOWTO/LVM-HOWTO/
You'll probably need to do /sbin/vgscan to figure out the lvm name then run
/sbin/vgchange -a y; mount /dev/VolGroup00/LogVol00 /mnt/whatever
can't remember how I arrived at VolGroup00/LogVol00 but think there is an explanation in the how-to
to automount I do in fstab /dev/VolGroup00/LogVol00 /mnt/whatever ext3 defaults 1 2 [note: I had run the vgchange prior to that once though, changed fstab and it comes up automounted now without doing vgchange.
Hope that is what you were asking.
Shawn