I was also searching for an answer to this question and finally got very angry with the Apple developers. As I discovered the scripting support for some of the preference panes is gone. However, I discovered this link

[Just use the favourite key method][1]

which I find quite a good solution. This does not solve your problem with scripting, I know, but I would argue that this is even the more elegant solution, because the best line of code is the one that was never written, or something.

I can live with this solution, I hope some others can as well. 

I post the solution here as well, because I am always angry when I find some solution that works and the link is broken: (This solution is stolen from LexFriedman at http://hints.macworld.com/article.php?story=20130621130534978)

But anyone who uses Hot Corners (which OS X refers to interchangeably as Active Screen Corners) triggers those mouse-controlled shortcuts accidentally sometimes. The solution is this: When you're choosing a Hot Corner setting from one of the drop-down menus, hold down your preferred modifier key or keys. You'll see the options change from, say, Mission Control to Option Mission Control" instead.

From then on, your corner will only work when you're also holding down the modifier key(s) you specified. Now, trips to the Apple menu won't trigger your Hot Corner shortcut—unless you're pressing your selected modifier key, too.


  [1]: http://hints.macworld.com/article.php?story=20130621130534978