Turning off Hero's "Auto-Pursuit"?

Is there a way to make a hero unit NOT automatically attack an enemy unit?

The problem is that I have small cliffs upon which I put creeps.
There is only one ramp up into the cliffs. When the hero is far away from the ramp and sees a creep, the pathfinding kicks in and he immediately takes off toward the ramp.

I'd like that to be the player's choice, not automated.

I tried setting the hero's acquisition range to 0, but that didn't work.

The creeps do the same thing, of course. When they acquire the hero target, they start running "away" toward the only pathway to attack the hero, the ramp. It would be great to change their behavior as well.

Is there a way to do this without scripting a new AI?

Thanks!

I could be wrong, but you can change the "acquisition range" to 0 and they wont do anything until they are attacked

The problem with the creeps you could solve by ordering them to hold the position by trigger while the hero has not yet passed the ramp. Once he passes the ramp, order the creeps to stop, so the hold position order is canceled.

Giving him peon attirbute won't make him auto-attack.

AIAndy, that will work for the creeps, thanks!

weaaddar, as for using the peasant or peon attribute, this doesn't work for the hero because then he runs away after every attack. I want it to be the player's choice of weather to attack, run away or whatever. I don't want the AI to take over, so I guess it's the AI that I'll have to change.