Does anyone know how to add or change hero footprints?

i have a few units that i like to add footprints to, does anyone know how to do that.

Footprints are an event tied to the model of the unit. You can simulate adding any model you want as a footprint by creating destructibles or Locust/Invulnerable units behind the unit as he walks using triggers. Or, you can change the model with some .mdl editing and import it into your map, but that'd add uber file size.

crap, oh well. giving an army of footmen um... footprints is not worth that much hastle. plus it would double the amount of units in the game.

If its for a cinematic-type thing you could just use special effects...