You can't. This was not included in the final public release of the OS. That's was so developers could start to think about how they might use it and if it would affect their software.
You don't need to spend $5, use the older XCode and it works like a charm! The Gestures are sweet, not sure why they didn't go ahead and activate them without folks having to jump though these stupid hoops.
Where do you download the older Xcode?
And I agree, apple should have just included them in the public release.