Hi there!
At SIG open the file
mambots/content/plugin_jw_sig/slimbox.js
and find the code
keyboardListener: function(event){
switch (event.keyCode){
case 27: case 88: case 67: this.close(); break;
case 37: case 80: this.previous(); break;
case 39: case 78: this.next();
}
}
The cases 37 and 80 are for the previous
and the 39 and 78 for the next
You can change them, checked out this site:
www.ryancooper.com/resources/keycode.asp
I hope I have been helpfull!