Hey, maybe I can help. Because I spend some time understanding the Axys Minigame Bonanza code, and created my own ledge hanging based on it. At first the Axys Minigame Bonanza doesn't use invisible boxes of any kind, it uses trace like Nipx says. Secondly the Axys Minigame Bonanza code isn't really tied up in the rest, it just looks that way. Check out the section in Axys code that starts with;
IF (movement_mode == 10){
this section is the code that makes the ledge work, only thing you have to ad is the activation code part, you can find that by searching for "movement_mode = 10;"

But it is really important that you learn to read the codes. Hope this helps.
Have a nice day, Molotov.