Sub-domains and virtual server owners

I am testing virtualmin usage in scenario that is common in cPanel usage. What I would like to achieve is to give non-root user ability to manage his own domain (web,email,DNS) and to create functional sub-servers, with different DNS domain name that has its own web site, and mail domain.
I have enabled
Using root account I was able to create virtual server with it’s own owner, that has (I believe) all necessary permisions
When I log to virtualmin as server owner, I can manage previously created virtual server.
I can not create new top level server, because I cannot choose account plan, but I believe that is by design.
I can create sub-server, but during creation “Enabled Features” is not avaiable.
When I create sub-server logged as server owner, new sub-domain has only “mail for domain” enabled, nothing else.
Is that by design? Is server owner supposed to have ability to create new sub-domains with separate web site and mail domain?
I am using virtualmin 6.02GPL, on centos 7 and ubuntu 16.04