The link that you gave was sk1nhd33t's own guide. That guide involves using of DSDT. Did you use the attached DSDT that sk1nhd33t used? That is pretty cool you made it to work, but why can't I make mine work. Of course, I repaired permissions and rebuilt Extension.mkext (also erased /System/Library/Cache/*). I even tried kext utility just to make sure. Placed it in /E/E - /S/L/E. Repaired permission in /E/E as well.

Just like sk1nhd33t, PleaseSleep works. But I'm still hoping for the native automatic sleep.

You got one obedient mobo there!