The 'L' button on my DS and SP are a little messed up, so I sometimes have trouble entering certain Blitz moves too, but yeah, the Down, Down, Left thing works just fine. Whenever the game says you need to input something like DOWN-LEFT, you really only need to push DOWN or LEFT.
Anyway, for my next question: I just got past Phantom Train recently, and I was wondering if there's a way to get the ghost to join your ranks permanently too. It's not really that useful, but I just want a full cast :D.