Unity tree creator and toon outline shading

Hello there.

I have created a tree using the tree creator and would like to apply something like the basic toon outline shader to the whole thing. Only problem is this isnt really supported as it wants you to use nature/treeCreatorBark or Leaves. I assume this is because these shaders support billboarding or something?

Anyway my question is, is it possible to overwrite these tree creator shaders so that they look more like the basic toon shader and if it is how would i go about doing it? I am entirely new to writing shaders so any help would be greatly appreciated. Or maybe someone knows of this already being done.

Thank you in advance. chip.