I don't think there is a way to do this... sorry. Maybe someone else knows how but I don't. THe only thing I can think is to change it to no damage base and one die with one side on it. What do you need it for? If the unit your attacking is a switch or something that wouldnt be fighting back or whatever, you could change its defense to something REALLY high. But thats only if you could, which I really doubt is what is actually needed in your map.... so sorry, I don't know how.