How do you beat the lemonade mouth game on Poptropica?

Lemonade Mouth is a high-school rock band, featured in the Disney movie of the same name (April 15, 2011). The ad-game appeared in May, 2011 to promote the release of the extended DVD on May 24, 2011.

The game is in two parts.
In the first part, there are 5 pages that represent clues to a combination. The key to the auditorium is locked in the Mel's Lemonade machine, to which five numbers are the code. Collect the pages, and enter the combination in the machine, then use the key to open the padlocked door.
In the second part, you are playing guitar in the Lemonade Mouth band, as fruit slices descend down three paths to buttons marked A, S, and D. As each of the slices reaches a button, press that key on your keyboard : A, S, D, or any combination of two keys. The meter at the bottom records your success - any that you miss will cause the needle to move from the right to the left. If it reaches the left side, you have missed too many and you fail the challenge. You can try again. When you win, you receive two rewards: a Lemonade Mouth costume (hair, sunglasses, shirt), and a carry-able yellow guitar.

*It may have been a considerable oversight that the rules of the A-S-D game are not explained anywhere in the game. When you select to start the game, it begins without exposition.