Unit beings casting: Storm Crow Form

Im trying to make a VampireLord (dreadlord) which can turn into a bat. The skill itself is easy, and the bat gains XP just if it was the dreadlod (but still different units). But, of course, it looks totally crap when a dreadlord suddenly is exchanged with a bat (dark hawk), and bat to dreadlord. So im trying to make the units run their death animation when they change form. I used "Unit begins casting ability - Bat Form", and then forced it to use its death animation. When the bat transform into dreadlod, it looks nice when the hawk falls down and a dreadlord is suddenly there (the bat death almost cover the whole dreadlord). But when the dreadlord change, nothing happens. After a test, i know that when the ability is used to change, it doesnt trigger "Unit is casting ability", only when transforming back.

Any way to do this?

Try "unit begins the effect of an ability".

ill try.... keep on posting guys=)