DrawMeshInstanced, How to sort z depth?

I'm instancing bunch of planes, but shadows get placed in the wrong order with them, because apparently with Graphics.DrawMeshInstanced they dont get sorted for transparency or z efficiency.
How am I supposed to sort them manually then?

 

Okay I got it working!

I had to add these to my ShadowCaster pass as well:

#pragma multi_compile_instancing
UNITY_VERTEX_INPUT_INSTANCE_ID
UNITY_SETUP_INSTANCE_ID(v);