Detecting SessionLock

Have others been able to capture the SystemEvents.SessionSwitch event to detect when the computer has been locked (SessionLock) and unlocked (SessionUnlock)?

I am running on Windows XP, coding in Visual Studio 2005 using .Net 2.0, but so not seem to be catching any events.

I have added the SystemEvents.SessionEnding and TimeChanged just to make sure that I knew waht I was doing and those worked.

But when I hit ctrl-alt-del and say "Lock Computer" nothing is caught.

I think I may have found the answer, but waiting for my local admin to stop by. Another post on MSDN asked the user if they had Terminal Services running. Once he had enabled Terminal Services eveything worked.

I hope I am that lucky and then try to convince the Security folks to please leave it enabled.