Here is a script that seems to work on my network... in fact here are three with their desciptions in the header bit. Save them as vbs and run with WScript 5.6.
You might try running script 3 first, to see if your License Server is enumerable (is that a word?)!
Will
Script 1 - AddLS.vbs:
'***********************************************************
'
' WMI VBscript to add a specified License server to
' Terminal server's registry
'
'***********************************************************
if Wscript.arguments.count<1 then
Wscript.echo "Script requires one argument, the LicenseServerName"
Wscript.echo "e.g. cscript AddLicenseServer LicenseServerName"
Wscript.quit
end if
Dim strServer
strServer=Wscript.arguments.Item(0)
for each terminal in GetObject("winmgmts:{impersonationLevel=impersonate}"

.InstancesOf ("win32_TerminalServiceSetting"
result = terminal.AddDirectConnectLicenseServer (strServer)
WScript.Echo "Method returned result = " & result
if err <>0 then
WScript.Echo Err.Description, "0x" & Hex(Err.Number)
end if
next
Script 2 - DeleteLS.vbs:
'***********************************************************
'
' WMI VBscript to add a specified License server to
' Terminal server's registry
'
'***********************************************************
if Wscript.arguments.count<1 then
Wscript.echo "Script requires one argument, the LicenseServerName"
Wscript.echo "e.g. cscript DeleteLicenseServer LicenseServerName"
Wscript.quit
end if
Dim strServer
strServer=Wscript.arguments.Item(0)
for each terminal in GetObject("winmgmts:{impersonationLevel=impersonate}"

.InstancesOf ("win32_TerminalServiceSetting"
result = terminal.DeleteDirectConnectLicenseServer (strServer)
WScript.Echo "Method returned result = " & result
if err <>0 then
WScript.Echo Err.Description, "0x" & Hex(Err.Number)
end if
next
Script 3 - QueryLS.vbs:
'***********************************************************
'
' WMI VBScript that queries the License servers configured
' for registry bypass.
'
' on the Terminal server
'
'***********************************************************
for each Terminal in GetObject("winmgmts:{impersonationLevel=impersonate}"

.InstancesOf ("win32_TerminalServiceSetting"

WScript.Echo "The License Servers are = " & Terminal.DirectConnectLicenseServers
next