How do I change the time zone of a user's session and not the local machine?

I'm in a situation where I need to set a user's time zone on a terminal server session. The trick is that the user is using such an old thin client, that the thin client does not have a local time zone to pass. I have created a script to change the time zone based on a membership of an Active Directory group. However, the script is changing the time zone of the terminal server itself instead of the user's terminal server session. I have included the script. Any suggestions on changing only the time zone of the user's session and not of the local machine?

Dim strHostName, strSearchFoR
Set objComputer = CreateObject("Shell.LocalMachine")
Set objShell = CreateObject("WScript.Shell")

strHostName = UCase(objComputer.MachineName) strSearchFor = UCase("Term")

If InStr(1, strHostName, strSearchFor) > 0 then
wscript.echo "Changing Time Zone to Arizona"
objShell.Run "CONTROL.EXE TIMEDATE.CPL,,/Z Us Mountain Standard Time"
End If