I doubt this is how they do it.
ARDGATE (free), RAZLEE's product, and several others use this to do it:
Read the link, and notice again the ARD in ARDGATE.
Dieter Bender, author of ARDGATE and Scott Klement (author of some
alternatives) recently had a discussion on this list. They both said the
other's solution is better in some cases and their solution is better in
others. Seemed like a total agreement, on both parts, to me.