I have a 1999 HSE, and managed to lock the keys in the car on the front seat. Problem solved in about 10 minutes, and without any broken glass.
1. You will need some wedges or small pry tools, or large flat blade screwdrivers. Wood popsicle sticks help, too.
2. Go to either back seat door.
3. As you're facing the door, gently start prying out the small quarter light window by starting at the top corner closest to the rear of the car.
4. Work your way across the top of the quarter light, gently separating the window and its rubber seal from the steel door frame.
5. Once it separates, gently pull from the top outwards, and you may have to insert some more wedges or popsicle sticks to keep it from going back into place.
6. Once you have about 1/3 of it separated, the window should pull out enough to reach your arm in and unlock the door.
7. Refit is the reverse of removal.