Access terrains "Alphamap 0" from within code

Every terrain with textures has "Alphamap 0" texture created inside Terrain Data. I want to replace it with my own; Now, inside code, I can just:

public Texture2D,

drag-and-drop it and go on.

But I want to fully automate the process. Is there any way to get to this particular "SplatAlpha 0" texture2D inside terrainData, using just editor script?

Like, this code: http://forum.unity3d.com/threads/412...atmap-download But I want to fully automate it.