I saw that vid too , at the start of the solo he does some legatos with his picking hand finger on the string to sound harmonics as you said ... This trick is used by Satch a lot in the G3 vid .

At the end of the solo he make a different trick , which is reversed tapping and sliding down the neck (chromaticaly sliding down the neck) ... It's not on the studio version but it sounds so cool.

BTW , he does the reversed tapping thing basicaly to show off , you can do it by normal tapping or even straight left hand legato (it will sound a little different in each case) ... But showing off live realy impresses your audience and friends. ;)