In my Xcode 4.2 project, I've created an Ad Hoc configuration and want to add the code signing entitlements file to the project, which is usually named Entitlements.plist.
In the past, I create this by selecting a folder in the project tree on the left, then context clicking, selecting "New File...". In the dialog that comes up there's usually a "Code Signing" entry in the iOS tree of the left -- but it's missing now.
The items that are there are as follows:
C and C++
Although I can't find out an actual reference saying that the code signing entitlements template isn't there any more by design, I have found a reference stating entitlements are not needed: https://developer.apple.com/legacy/library/technotes/tn2250/_index.html#//apple_ref/doc/uid/DTS40009933-CH1-TROUBLESHOOTING_GUIDE-CODE_SIGNING_ENTITLEMENTS.
So I'm assuming it's by design in newer versions of XCode.