Logic Pro 8 Auto input monitoring not working for me


I was hoping that in L9 Auto input monitoring would finally work, but I'm checking it now on my macbook with built-in audio, and when I set auto punch in and out points and then hit record on a previously recorded track, I won't hear what's on that track prior to the punch in point.

Sometimes it almost seems to work (it plays like halve a second of the
previously recorded audio), but then continues without any sound.

Anyone else got it to work? I got software monitoring enabled.