Thank you, this worked in my 2007 987 base.I read and re-read the manual and for me, a step was missing. Here is what I did for my rolling code to get it working:
1. Press I and III until the red LED flashes
2. Press I (or II or III to set up the Home link button to be assigned)... Maybe I am a bonehead but I just did not see this step called out in the manual.
3. Press and hold the original clicker at the front of the right bumper until the turn signals flash.
4. Press PROGRAM on the garage door opener
5. Press "I" on the Homelink until garage door moves then stop. It took 7 presses for my rolling code was aligned between the car and the garage door opener.