Found this thread of posts while combing the 'Net trying to fix my Stanley keypad. The websites for AAARemotes and Stanley-Garage-Openers have nearly complete instructions. There is one key piece of information missing in the section "Setting the Radio Code." Follow their directions up to that point, but add the following step:
After pressing the Radio Learn key twice, you must enter the access code (1234 for factory preset, or the new code you entered in the previous section) and THEN enter the radio Code set on your power unit, then press Radio Learn once more.
So, to summarize, you may wish to change the instructions to read:
"B. Enter the "Access Code" that you selected, then enter the "Radio Code" that you determined is set on your power unit."
Thanks for completing the picture. My keypad now works perfectly.