Using setx.exe while using PowerShell Remoting

Question

Hi,
I am using the Invoke-Command with a Session to execute some installers on a remote computer. This works fine but for some reason setx.exe (to set Environment Variables) will not work as expected. When I create a new computer Environment Variable I am using
the following command which works great:
$process = Invoke-Command -Session $Session -ScriptBlock {
$result = Start-Process -FilePath "setx.exe" -ArgumentList 'MY_PATH "C:\Program Files\MyApplication" /M' -Wait -PassThru -Verb RunAs;
However, when I try to edit a current Environment Variable like PATH it does not work. I use the following code:
$process = Invoke-Command -Session $Session -ScriptBlock {
$result = Start-Process -FilePath "setx.exe" -ArgumentList 'PATH "%PATH%;%MY_PATH%\bin" /M' -Wait -PassThru -Verb RunAs;
When I login on the remote computer and use "echo %PATH%" from the command prompt it prints the following:
%PATH%;%MY_PATH%
While I was expecting:
%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files\MyApplication\bin
Any idea why I cannot append with this way to an already existing Environment Variable? The commands work locally when I execute it from the command prompt.

Answer 1

Hi Anna,
Thanks for your reply. I executed your code and the NEWPATH variable is created but the value is "%PATH%;%MY_PATH%\bin". So it does not seem to reconize other environment variables on this way. Any idea why?
Thanks
Ps. the complete code I am using is the following:
try
$Credential = Get-Credential -UserName ("{0}\{1}" -f $env:USERDOMAIN, $env:USERNAME) -Message "Enter your credentials"
$Session = New-PSSession -ComputerName "TEST2938" -Credential $Credential -Authentication Credssp
$process = Invoke-Command -Session $Session -ScriptBlock {
setx.exe NEWPATH "%PATH%;%MY_PATH%\bin" /M
finally
if ($Session -ne $null)
Remove-PSSession $Session