I am sure that you either realized this or moved on, but advised most of these guides a bit: you can often download the completed code from the website. I did this and downloaded it in Xcode 5.0, and it works great. Here is a screenshot of the plist entries (under Resources / ScaryBugs -Info.plist) for the document and export:

Another way to change document types in Xcode is through the project information (select the project in the Navigator, then the target in the list of projects and goals, then the information tab). Here is a screenshot of what it looked like to me:

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