When you tap, you don't pick any notes, you use hammerons/pull offs to sound the notes that your tapping finger doesn't hit.

For instance:

|---12h13t15--12h13t15p13p12---| x3

You would pick the 12, then hammeron the 13, tap the 15, then pulloff the 15 so the 12 rings again, then after you hammeron and tap to the last 15, you pulloff to 13 then 12. You may pick right before or right after a tapping lick, but not during. If thats the case, try using your middle finger while you pick stays in its place, ready to hit the string when needed again.