opening AC3 audio files

[Jane Jordan]

Hi there.

i have a little program called Mac3DEC which decodes AC3 files and  
turns them into .aiff files.  I can manually select the files in  
mac3dec, but it's tedious.  What I want to do is use command-o to  
open the files, but whenever I try, it says that the ac3 file is a  
mail document.  When I try to change the application from Mail to  
mac3dec, it won't let me select the application.  Does anyone have  
any suggestions how to fix this?

Jane