okay here is the full run down of what to do :P
1- program the hand held remote to one of the button like the thread here
2- open that box with ur car about 3 feet behind that box.
3- Open the little cover to the little box inside the black box. Its like two screws
4- press the learn button (push and let go) it will flash dot....dot...dot
5- go into your car press the button u programed ur remote to hold it down then press it 2 more times press hold...let go...press...press. bingo

 

some notice:
your homelink unit might be set to different region. With these three buttons it could changed. That is the problem I had. I has some like 3 or 4 regions, that changes frequonses from Euro to USA and some others..

ask dealer for operating regions for homelink. It is easy to do..

 

I dont think its a region thing for him its the learn button but he can also just try a friends garage door

 

Ok, easy, but one question.. how do I know that the homelink button has been successfully programmed by the hand held remote? Will it stop blinking? coz when I tried programming with my remote alone, after 30 secs the light in the homelink button stopped blinking.

 

pres and hold the button on your homelink (mirror) not the push and release 2-3 times. The learn button on the gate. press it but "DO NOT HOLD IT" that would kill the memory and run if that happens

 

the light will flash more rapidly once it has taken the code. 2nd step for the rollin code is just to hold it. Your gate will probably open as you hold it down. may take about a few seconds and get your car as close to that box as possible. a friend to help would save you lots of running back to the car.

 

yups as passnu2 describe in the last two post :P