2DSceneCapture to Variable / Thumbnail Maker

I’m trying to make a Thumbnail Maker for HUD thumbnails
First I made a Greenroom like

inside of a 2DSceneCapture Blueprint.

The SceneCaputure gives the thumbnail with green background to a RenderTarget.
The thumbnail would be finished if the RenderTarget would filter the ChromaKey by the given settings. … it does not filter.

So I need to post process it like in this tutorial.
[Steamroll’s 3D User Interface][2]
In the end he made a material. BUT I want to:

  • call the GreenroomBlueprint
  • change Static Mesh
  • get updated RenderTarget Texture
    (works fine 'til here!)
  • filter ChromaKey
  • store Texture to HUD variable

repeat for next Mesh.

How to filter ChromaKey from a texture, or use the material from tutorial dynamically for different meshes ?
regards