Overlay invisible img onto Flash password requirement

My site is SheetMusicEditor dot com and I want to place an invisible png graphic over the print button. I want to allow my visitors/users 1 free print so they can see how sharp and clear my editor is prints. When they click print I want the entire page to to dim and a window/box to appear that says Hey you get 1 free print. After that you will need to buy annual token for $1.99 via Paypal in order to print again. Or click here to enter your token code: 00000 etc.. Click here to close and proceed with your 1 free print. Then the print button should work and the invisible png moved out of the way of course. When clicked for the 2nd time it should Hi! You've used up your 1 free print, you must purchase an annual token to print. And I guess there would be a cookie involved. I would need to have a password / token code list .txt file I could edit and add passwords to myself and delete if I find them on forums or something. I think this is a simple scripting job for anyone with the skills. I would have done this myself but my .fla flash source file is lost or corrupt if I have it from what I found.