i currently have this in my map. what i do is make a behavior thats applied when the unit dies, then i think after 4 seconds in the actor events i paused the animation, so its still when its on th ground and doesnt animate through the ground.
i actually made it spawn a new unit, and just took out the death model, so its a new fresh model that looks like the old one dying, so my corpses are actually alive, i did this so my units can pick up / move / blow them up.