No, I meant call scripts, as in, you'd need to change some stuff in the script editor before you could use call scripts to change things
What I meant was you'd have to make a game class to store all the variables for sound effects, aand you'd have to then overwrite the Sound module and make it play from your new game class instead of the data class. All in all, it's a fairly easy project.
EDIT::
Since I had some time, I decided to write the necessary script to allow for in-game modification of the System Sound Effects. Here it is:
http://rmrk.net/index.php/topic,25124.0.htmlTell me if you have any problems with it.