How to setup docker registry with non-bundled nginx

I struggle to find working instructions. I'm running the omnibus install on ubuntu server configured to use a non-bundled nginx as described in the docs (https://docs.gitlab.com/omnibus/settings/nginx.html#using-a-non-bundled-web-server)

But these instructions don't seem to take the registry feature into account or I'm missing something. Is there already a document describing the additional steps necessary?