Howto do vbox:// access to a remote system.

I only get reset connections on remote connections.
So something is wrong, Q is what. 
(tried things like: vbox://thehost.local/   & vbox+ssh://thehost.local/
both with & without username).

Sofar only vbox:/// seems to work. (on a workstation).
So how to manage a headless server running VirtualBox?
