heres what you do in a 2004:
-get in your car, put the key in the FWD position to allow you to set any controls were you want them, click off the radio, roll up the windows, etc.
-take the key out.
-put the key in, and cycle it BACKWARDS to the "ACC" position and then forwards one click. repeat 4 times.
-with the KEY STILL IN, kit your drivers door lock button UP. Horn will chirp.
-Remove key, and get out quick, close the door.
The car will go into hibernation mode in about 30 seconds, give or take. Before it does hit hibernation, you can arm the alarm if you want- it wont function while in hibernation (IE you can open and close the hood/trunk without it going off) however, when the car comes out of hibernation, the alarm arms itself. If anything is open, the alarm will go off, the doors will not open, and you need the key fob to disarm it.
to remove the car from hibernation, push the DRIVER exterior door handle. If the alarm is armed, disarm it. if not, door will pop open, hop in and put the key to the FWD RUN position. Hibernation mode is exited in RUN.
Hope that helped!