Cinecamera to composure & widget

Hello

I´m trying to get the cinecamera view to a widget using cg_element and composure composing. If the transform pass is used, the material stays default. If output to render target is used, the result is black. Any idea what do I do wrong. This used to work in UE4.27.

Any help would be appreciated. On Youtube Aiden Wilson is doing something similar, but he unfortunately says at 1:37 that “this probably a tutorial for an other day”. Can not link the video here, but it´s called " Using a Tracked Blueprint Camera with Composure in UE4 (Tutorial)".

Yours, Ramses

PS. On the screenshots, the cinecamera view should be seen on the plane.