Help Compile Three20 libraries in a Xcode 4/SDK 5.1 project

We have a xcode (ios) project that we need help in compiling with the latest iOS 5.1 and xcode 4.3.1 or higher. This project has Three20 libraries which used to compile great for iOS 4.x and 5.0. However with iOS 5.1 its not compiling. We would need the entire build compiled successfully and also proper documentation for the steps involved so in future we may do it ourselves.