This is an excellent guide, many thanks! I'd been looking for a way to around this stupid restriction for eternity and I'm glad someone much smarter than me figured it out.
On another note why is such a simple modification so cumbersome? I love that you can do things like this in Linux don't get me wrong - open source is great for reasons just like this, but seriously recompiling the whole panel just to change one setting is a little like overkill. I think this UI restriction needs to be addressed in a future release, maybe a gconf option or setting? (though I'd imagine this wouldn't be a simple task!)