What I don´t understand is, why this problem does not occour anywhere else for me, only in A7.
Even my probably very dirty postprocessing class for irrlicht (rendering with D3D9) works fine. All it does is to create a screenaligned quad with a shader on it. This is rendered into a texture, then there is another screenaligned quad with a shader on it which gets passed the texture and so on, the last "stage" renders to the screen.
I thought that is how it is basicly done? So what is different in GameStudio?