I see.. The armor points seems not effecting at all..
Hmm. Okay, try playing around with different numbers for the toughness in your .veh file; like maybe 999.0 and see if that makes your "beast of burden" survive longer, in tandem with a higher number for the armor (9999). I was just reading in the template.veh file that any number ending with .5 is half damage on toughness, so maybe you could try using 999.5 as well.
Still no change. I guess I just need something like that malfunctionArmorLevel for animal vehicle eh? But it's fun to change the other things like move speed and camera position etc..