I've had (probably) similar problems trying to edit conditions:
I wanted to make a monster that reacts in a particular way to being attacked by Edge's Dart command, but it wasn't working.
Likewise, I wanted a particular reaction to a character using the Item command with a particular element (say, a specific reaction to lit-bolt) but it seems the game treats elemental attack items as spells in that respect, so the condition has to be an elemental spell in order for an elemental item to trigger a reaction.
Other custom conditions (that I can't remember at the moment) didn't work either.
I was kind of hoping that once the monster editor was released, you would have figured out whatever it was I was missing.
Maybe the game isn't really capable of observing all of the conditions the human mind can conceive?