Custom PostProcess in Plugin

I am currently developing a custom Tonemapping and so far I just edit the Renderercode itself, wich leads to the Problem, that everytime a new Version is available, the project needs to be upgraded by hand. The Question is, how can the Shader be in a Plugin and still get a Place in the Postprocessinggraph. As far as I am informed all these Headers are private and do not get exported.
Thanks for any help on this.