You can easily install two versions of Xcode on your system (I installed both Xcode 4.4 and Xcode 4.5 beta 3), and my iPad is upgraded to iOS 6. I can test current applications on my iPad (we are working on these applications) and deploy them, of course, using Xcode 4.4. These applications must have an iOS 5.5.1 or lower goal and should not use any iOS 6 add-ons.
Installing both versions of Xcode is quite simple, as version 1 (4.4) is installed on the Mac App Store, and beta version (4.5) is installed as an .app file that you can drag and drop into the application folder. It has a different name, so it does not overwrite your version 4.4.
In order for Xcode to recognize your iOS 6 device, you need to open version 4.5 so that Organizer collects data from your device, and then you can open Xcode 4.4, it recognizes the device image and uses it (although you cannot iOS 6 with Xcode 4.4, you can test iOS 5 app on an iOS 6 device)
Hope this helps you
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