You cannot use a reserved property

Hi!

vRA 7.4 distributed environment.

Blueprint for a Windows 2016 machine, we are using the CloneWorkflow, clone from a vCenter template and are using a Customization spec.

There are 3 disks in the template, when deploying, only the C drive is active so I want to use VirtualMachine.DiskN.Letter, VirtualMachine.DiskN.Label and VirtualMachine.DiskN.Active as custom properties to set these drives active after the deployment.

But it's not working, it says "You cannot use a reserved property" when adding these properties to a disk in the blueprint.

What am I missing? Where should I use these properties if I cannot add them to the disk? Should I enter them in the Property Dictionary?

I tried it on a Create BasicVMWorkflow because I thought is was an issue since we are using a template but I have the same problem.

I normally use a Powershell script to set this but I figured, why not using those properties but I cannot get it to work...

Thanks!