Thank you Philippe for your fast response.
No, I did not choose the Multi stereo/mono format in the record dialog. This also still shows only 2 meters, just as with stereo.
There is no surround option to choose from.
In Montage I can create a 5.1 file. I cannot do that in the Audio Files editor / the place where you normally can record single files.
I have set up the full surround settings in the VST Audio Connections.