Render Target to DMI Texture Parameter

I’m trying to make a datamoshing post process effect but I’m stuck at the very first hurdle. It seems that neither “Create Render Target 2D” nor the canvas equivalent return anything. Everything else seems to be working because I can see the white Clear Color fading away when I start the game.

I also tried using a Scene Capture 2D component and it seemed to work, but it looked like a different viewpoint with a noticeable drop in performance. Any ideas?