Terrain Layers

I am trying to make use of the new terrain system and I bump in to many many issues.

Does anyone understand how to make a new terrain paint for existing terrain. Say you want one summer terrain and one winter. When trying to create new palettes everything becomes wierd. First if saving as new, and the making changes, going back to the old one will also have changed. Does anyone know how to create a multiple paintings for same terrain?

 

How do you mean? like if you have a mountain range, you want one with ice and the other side without? sorry just trying to understand what you trying to do first.