Problem in transparency with Transparent/Diffuse

Hi all,
I has a problem with the transparency of a plane.
This is the code to create the plane et apply the shader and texture.

obj.renderer.material = myMaterial;
obj.renderer.material.shader = Shader.Find("Transparent/Diffuse");
obj.renderer.material.mainTexture = Resources.Load("echaffaudages_01", Texture) as Texture;

alt text

I dont understand why my plane is totally transparent and don’t work with the alpha of the .png file.
When i use the same file directly in unity, create manually a shader diffuse/transparency
and put this file it work perfectly.
Thanks for your help !

I would assume that the transparency of the color you have on the material is set to 100% transparent.