Transparent texture support in toon shader (Unity 3.x)

New to shader, I've read other posts about blending alpha info from main color into the texture. But how to support transparent texture?

http://answers.unity3d.com/questions/23358/add-alpha-information-into-the-standard-toon-shader

It turns out my mistake of reading the original post I linked above. Which already support transparent texture well. I didn't notice that toon outline shader have a UsePass of toon shader, so I only modified the toon outline shader.