My ext drive has 1 partition each for my WinXP and Ubuntu files (I am dual boot). Both have the same underscore issue. Gparted shows the mount points of each with the underscore present. The original name without the underscore is absent. I have normal backup operations as long as I use the one containing the underscore.
You've got the best guys in the business helping you in the Ubuntu forums; OldFred in particular knows the system quite well. And Cheesemill's contribution is a great way to head off troubles... -- Jim Kyle