that guy is me, what is needed it the vmware.hv.helper module from the powercli example scripts at GitHub - vmware/PowerCLI-Example-Scripts
What you can now do is this:
Set-HVMachine -HvServer $vcs -MachineName machine.fqdn -User "domain\user"
or
Get-HVMachine -MachineName machine.fqdn | Set-HVMachine -User user@domain
thanx to another contributor of the module 