SceneCaptureComponent2D and post processing in widget.

I use SceneCaptureComponent2D and rendered texture from it in Widget for showing picture in picture. The component captures some objects with post processing (custom depth for outline effect) which is not displayed in the rendered texture. As far as I know, it’s not a problem to show the effects, if the rendered texture belongs to PostProcess domain, but mine belongs to User Interface, because it’s the only acceptable domain for textures in Widget. So, how can I display post processed image in widget?