I have confirmed that the procedure posted by the_saint above also works on the 1996 MPV, but not the 1993 MPV.
The 1993 MPV uses an IR signal, while the later models use an RF signal so it is not necessary to point the transmitter at the receivers in the car. Nice improvement, and the programming instructions must have changed too. Probably not much though.
So, anyone know the recipe for the 1993? KeylessRide Home sells instructions for <$15, but says it needs an operating remote. Don't know why, and don't know if mine is good. It used to work but stopped. Replaced battery, but nogo ever since.
Who has a reference to this info? There was a lot of forum correspondence in the past to help with the newer models. Hope it returns. I'll be grateful.