The artificial harmonics are played as you were told before, but I learned that they are "geometrical". What I mean by this is that you have to pick the harmonicin the middle, at 1/3 or 1/4 of the distance between the bridge and the fret you are fingering. Thus you have to do a lot of experimentation. For example: I use a 22 fret Strat, and an harmonic in the 21st fret of the third string must be picked +/- ovetr the middle pickup, otherwise it won't come out. You have to be really precise with this.