Stop a hero's mana regenerating normally

I want to stop the hero's mana regenerating of its own accord, i set the mana regen to 0 in the editor but the hero still seems to regenerate its mana :S (kinda defeating the point of the setting :/)
Is there a way other than working out the increment and adding a trigger to "hero mana - x" every few seconds to stop it

thanks in advance

They are regenerating due to intelligence. Set that to 0 in the gameplay constants.

thanks :)