How do I configure xorgxrdp to mirror my current display?

[ghost]

I am trying to set up xorgxrdp as a second device in my xorg.conf.d, so that when the system login manager starts X11, it is automatically set up to display the picture both to the default monitor (connected to the real video card, vc4), and to the virtual monitor provided by xorgxrdp.

Just copying the provided xrdp/xrdp.conf to xorg.conf.d lets me start Xorg with the virtual driver, and I can even connect to it using x11vnc. However, when I am trying to change anything using xfce4-display-setting, the program crashes, and xrandr does not list my physical monitor and the physical card. Apparently, they are not detected if there is an explicit xorg.conf.d/file.conf

How would I properly make xorgxrdp be a mirror of my real device?

Perhaps, there should just be a proper configuration file?