Help modifying senocular collapsing menu

Found here: I use the middle style. This is perfect for the actionscript-challenged like myself, but I cannot seem to figure out how to modify the buttons beyond them telling other things what to do. How do I make the buttons themselves do different things if clicked? Such as change to a different button, or make a plus sign turn into a minus sign to signify opened or closed.

Any new actionscript I write into the movieclip, or if I make the buttons movieclips to allow actionscript in them, is cancelled out by the actionscript that makes the whole collapsing thing work. Only buttons seem to work, or movie clip loops (which have no actionscript.) I can make some actionscript work, but then the collapsing script doesn’t work. I can’t seem to do both.

Any help would be greatly appreciated. I’ve already given up on trying to find a way to add another level to the menu, but this particular problem didn’t seem totally impossible. Thanks.