On clipEvent with movie clip....help

Hey, I have a movie clip that has its own timeline animation. When the mouse is clicked on the movie clip, the animation starts and then is removed. So, I can do this easily when the movie clip is dragged on the stage, I click on it and add the on clipEvent(mouseDown) script.
But when the movie plays, I need to have the mc generate on screen a bunch of times. When its in the library, it doesnt have the on clipEvent(mouseDown) script and I cant figure out how to add the script to the mc in edit mode when its in the library, I keep getting errors.
Any ideas?