After new Windows 10 Professional has been installed on VirtualBox, install remote management tool and enable Hyper-V/Hyper-V Management Tools on Windows Features on or off.
Add server 'XENON' to Server Manager and set 'XENON\Administrator' as manager account.
Following command seems be requierd to enable 'Computer Management';
Allow MMC & WMI through the Windows Firewall, on both
netsh advfirewall firewall add rule name="Microsoft Management Console" dir=in action=allow program="%windir%\system32\mmc.exe" enable=yes profile=private
netsh advfirewall firewall set rule group="Windows Management Instrumentation (WMI)" new enable=yes