Awhile back i was viewing some info on one of the videos and some complaint came up about how the guy was pulling off a harmonic. Two ways i found listed already(i would give you credit if i could refind the post sorry guys). It can be done these different ways and give off and awesome sound all three ways.

First Way:
Depress Trem Bar
Pinch Harmonic

Second Way:
Hit an open string (best one is the G).
Depress the bar so the strings flopping around sorta loosely.
Tap your fretting hand on a "harmonic fret" same string. (I like the 3rd fret the best)
Then pull up the bar.

Third Way:
Hit an open string
Depress the trem bar so the strings flopping around kinda loose.
Hit the same string with your pick(barely touch it)(i find it best to go about 4 inches from the last fret to hit it with the pick)
Release the bar

Thats it