I had dealt with problem far too often. I have found that including restkit has been quite painful and I don't remember what I did to repeatedly fix those issues because it was always something new that broke. I do have a suggestion as to a better solution: use cocoapods. If you haven't used cocoapods, then go check out http://cocoapods.org  It's a dependency management framework. It will download and install RestKit (and other APIs you choose) and will handle all the project settings for you (it will create a workspace that will contain a separate project for all your dependencies).

I know that isn't the answer you were looking for but cocoapods becoming a de-facto standard in iOS and OSX dependency management.