I am writing a powershell script to set up some HyperV VM’s however there is one step I am having trouble automating. How do I check the box to allow Remote desktop access from the RemoteApp settings programmatically?

I can set up all of my customizations I need by doing
#build the security descriptor so the desktop only shows up for people who should be allowed to see it
$remoteDesktopUsersSid = New-Object System.Security.Principal.SecurityIdentifier($remoteDesktopUsersGroup.objectSid[0],0)
#get a copy of the WMI instance
$tsRemoteDesktop = Get-WmiObject -Namespace root\CIMV2\TerminalServices -Class Win32_TSRemoteDesktop
#set settings
$tsRemoteDesktop.Name=$ServerDisplayName
$tsRemoteDesktop.SecurityDescriptor= "O:WDG:WDD:ARP(A;CIOI;CCLCSWLORCGR;;;$remoteDesktopUsersSid)"
$tsRemoteDesktop.IconPath = $IconPath
$tsRemoteDesktop.IconIndex = $IconIndex
#push settings back to server
Set-WmiInstance -InputObject $tsRemoteDesktop -PutType UpdateOnly
however the instance of that WMI object does not exist until after you have the above box checked.
I attempted to use Set-WmiInstance to instantiate and set the settings at the same time but I keep getting errors like:
Set-WmiInstance :
At line:53 char:16
+ Set-WmiInstance <<<< -Namespace root\CIMV2\TerminalServices -Class Win32_TSRemoteDesktop -Arguments @{Alias='TSRemoteDesktop';Name=$ServerDisplayName;ShowInPortal=$true;SecurityDescriptor=$securityDescriptor}
+ CategoryInfo : NotSpecified: (:) [Set-WmiInstance], ArgumentException
+ FullyQualifiedErrorId : System.ArgumentException,Microsoft.PowerShell.Commands.SetWmiInstance
(also after running the command and getting the error it will delete the instance of Win32_TSRemoteDesktop if it already exited and un-check the box in the properties setting)
Is there any way to programmatically check that box or can anyone help with why Set-WmiInstance throws that error?
You could use the Remote Desktop Services Provider for Windows PowerShell module if you are running windows server 2008 R2.
You can read up about it on technet hear is the link.
I used this guide for all my needs .