SWSE Placed Explosives: How do they work?

[LibraryOgre]

I would let the mine (automaticaly) hit the creature that stepped on it, but require an attack roll against everybody else in range (I would go with either +5,+10 or depending on the character that planted the mines, but the books don't help much).

I would give the mine a Reflex save value, perhaps with a penalty for whoever stepped on it, and a bonus the further away one went.