Keypress sound of letter

I am a teacher on a primary school and am trying to make a game for my students.
I want the student type letters and the computer tells them which letter they’ve pressed.

Every letter from the alphabet I spoke and saved in my computer.
At this site http://www.bensilvis.com/?p=146 I’ve found an actionscriptcode.
Now I want to change the code so the computer links the letters to my audiofiles.

Can anyone tell me where and how I must do this?

Hope someone can help me.

Kind regards.