Fragment Shader Normals in DepthNormalsTexture

I'm wondering how I can go about storing the normals from a fragment shader so that they are accessible when rendering a DepthNormals Texture. The normals from the fragment shader are derived from a normal map. The surface shaders in Unity handle this wonderfully which can be demonstrated by placing a simple mesh with a material with the diffuse normal map shader, in front of a camera and rendering the depthnormals texture. The normals from the normal map are accounted for when rendering the...

Fragment Shader Normals in DepthNormalsTexture