Thanks for the replies. I looked in the manual, and indeed there are instructions. The instructions are as follows:

Turn the key to position 2, then to postition 0
Take the key out and old the lock botton for 15 sec, after that press the unlock botton 5 times.

I've tried it a couple times, but nothing happens. I close the door before trying. What could I be doing wrong. By the way its a 98 ML.