Terrain Tree Rotation/Randomization

I created a tree with the tree creator from Unity. Now, I am using the tree painting for a terrain object. Yet, I see that it is impossible to rotate the trees...

What is the quickest way to rotate or randomize a tree in my situation?

**I am using Unity 3.1 on Windows 7.

There isn't a way to rotate trees, because it needs to billboard them. You can create several trees of the same type that are rotated differently in a 3D app, and use those as separate trees.