Ok, this is what I want. I want a HDRI reflection on a object without seeing the HDRI image on the back, is that possible?
I know how to set up a HDR image as a worldtexture and rendering with yafray etc. and even the rendering is perfect but I see the HDRI image on the back.
How can I make the same image (with the HDRI reflection on the image) without seeing the HDRI image on the back?