Include / Linking "file not found" with Xcode

I am trying to link my plugin against FbxSDK, a library provided by autodesk. The library is located at “/Applications/Autodesk/FBX SDK/2015.1/”, however I made a copy to “/Applications/Autodesk/FBXSDK/2015.1” to ensure that the space in the name wasn’t causing the issue. The directory structure is the standard for a library, with an include and a lib/release and lib/debug directories. I have added “/Applications/Autodesk/FBXSDK/2015.1/include” to the project file under HEADER search paths and selected the recursive option. fbxsdk.h can be found in the top level directory of this include folder. I also added it to the user header search paths and selected the always include header paths option. I have further added the appropriate lib directories to the library paths section.

My Problems is that, despite the fact that I have included the library headers in the project file, I still get the error ‘fbxsdk.h’ file not found when using either #include or “fbxsdk.h”. I was wondering, therefore, whether unreal does something strange to the xcode compilation process that would prevent this from working? Normally, I would expect the program to now be able to find the header files and link against the library.