It’s true, Pinan Three does have a Ki building technique in it. Actually, many of the techniques of the basic Pinan Kata, or Heian Kata as they are sometimes called, have ki building techniques in them.
The specific technique is the very first move. You won’t see the ki building in the form, however, it happens in the technique. If you’re interested, check out the technique in the Monster Journal. It’s in the second issue (the first issue has a great technique in it, too), and you should just click on Pinan Three Ki Technique to get to the Journal page.
The Monster Journal is a short, free, online martial arts magazine. There are a few mags out there, but this one is pretty concise, and very martial arts oriented. You can read it online, or download it. Make sure you enter the contest, it’s a chance to win ten free martial arts books (on CD).