2007 has this feature (I guess they heard the 2006 complaints!). I assume you also followed the other steps that you didn't mention? (setting parking brake; pushing & holding brake pedal; moving the shift lever out of park; put ignition back to I position & then move the shift lever back to park?) It also sounds from the instructions that you have to wait for the third click (one when you first press & hold the unlock switch, one 5 seconds later (activating driver door only) and one 10 seconds later (activating all 4 locks) - maybe you're just not waiting long enough....

I will try the steps today as well and see what luck I have (car came with the driver only unlock set and I haven't felt the need to try to change it.)