Nice, would you mind to share how you have done it through the API ?
I have tried those two without success:
curl -k --data-urlencode 'reference=docker.io/hello-world:latest'...
An API endpoint seems to be in develomment: [pve-devel] [PATCH storage v5 13/17] api: add storage/{storage}/oci-registry-pull method.
Otherwise it just does skopeo copy docker://$reference oci-archive:$path/$filename.tar...
