i have a marshall valvestate and a boss ds-1, with a hot rodded strat. i get almost vai's sounds perfectly by setting the amp on the clean channel to bass: 4.5 mids: 5 treb: 9 for the bright clean sisters type of tone and use the fourth position on the selector.

for all his other stuff, i set the amp to bass: 7 mid: 8 treb: 5.5 and get the boss settings like dist all the way, tone about 9 o'clock, and level all the way

if ur using the fist settings with dist, have the same settings on the boss but bring the tone down to 8 o'clock to compensate for the bright sound.

that'll give u the basic steve vai sound, but it changes with the way u play as well.

as for the pedal u have, i havenn't the foggiest...