Set VM Storage Policy to "Datastore Default"

How can I set the Storage Policy to "Datastore Default" ?

I know how to set based on a specific profile ID but I don't know what is the "Datastore Default" ID.

I found the PowerCLI script https://communities.vmware.com/thread/583674:

$vmName = 'MyVM'

Get-VM -Name $vmName | Get-HardDisk | %{

    Get-SpbmEntityConfiguration -HardDisk $_ |

    Set-SpbmEntityConfiguration -StoragePolicy $null -Confirm:$false

}

with JavaScript is not working in this way:

profileUniqueId = null;

var deviceChangeSpec = [];

var changeSpec = [];

var myVcVirtualMachineConfigSpec = new VcVirtualMachineConfigSpec() ;

var myVcVirtualMachineDefinedProfileSpec = new VcVirtualMachineDefinedProfileSpec() ;

myVcVirtualMachineDefinedProfileSpec.profileId = profileUniqueId;

changeSpec.push(myVcVirtualMachineDefinedProfileSpec);

myVcVirtualMachineConfigSpec.vmProfile = changeSpec;

I receive the error:

"com.vmware.vim.vmomi.core.exception.MarshallException: VirtualMachineDefinedProfileSpec required property profileId not set"

What is the right approach with vRO?

Thanks