Diffuse bake alpha

It’s simpe. I have a plane. On that plane is a texture of a leaf with alpha transparency. Works when I render/switch to rendered preview. Now I want to bake that image of a leaf to another plane, so I have 512×512 texture (instead of some random resolution)

Above is the node set up for the transparent leaf

[![enter image description here][2]][2]

And the material for the “low poly” plane that I need the image baked to, is just an image texture with an empty image connected to diffuse connected to surface output. When I bake it, the places that are transparent in the first material, just become black instead.

https://www.dropbox.com/s/bhmh1l6ikcuiyim/Dandelions.rar?dl=0
Here is the file in case anyone wants to see it-it’s ment for UE4 btw. The top layers are the “low poly”, more to the right, the lower the texture resolution is, and below them, there are the coresponding “high poly models”

Joke question-How tall are dandelions usually? 15-25cm?