vCloud scripting what permissions are needed for GetGuestCustomization?

[GScully42]

I get to this part in my script,

$Vapp is a deployed V-App and is not null.

$custom = $Vapp.extensiondata.getguestcustomizationsection()   

$custom.ComputerName = $JailName

$custom.UpdateServerData()

And I get an access denied on  $Vapp.extensiondata.getguestcustomizationsection()

Exception calling "GetGuestCustomizationSection" with "0" argument(s): "Access is forbidden"

vSphere 5.5u2

vCloud 5.x

Hence the question, what level of permissions do I need to accomplish this, is Power user good enough or do I need to be an Admin or something else?

Thanks

[Sreejesh_D]

i have used it in the past. I think the user should be a system administrator or organization administrator.