Question about Auras for Heros

Does anyone know how you make an offenssive aura- for instance an endurance aura that lowers speed by -10% instead of +10% When I type -10% it goes to 0. I've seen other maps with negative aruas but when I goto modify them it goes to 0. Anyone have any ideas or no how to fix this? Thanks if you know how.

In the WE go to file > preferences and under the general tab there should be an option which says "Allow negative real values in Object Editor" check that box.

You can also hold shift while you open it type it in and hit ok, then release shift...should work.