I've posted this post in 1 of you other threads, but for some (so far unknown) reason it got deleted.
Anyway, play the animation and set animation speed to (0 - 20)%. This will cause the animation to be played backwards. Do remember that this could look weird on some models, but you got to test which are suitable and which are not. I'm not entirely sure if it is required to have the unit played the death animation completely for this to work, but if so: play the death animation, set animation speed to 10000%, wait 0.1 seconds, set animation speed to 0%, play death animation and set animation speed to (0 - 20)%.