Mopub Integration with Unity 4.5 and Xcode 6.1

Hi folks, This is my first post in this forum. I had successfully integrated Mopub SDK with older versions of Mopub/Unity/Xcode. But I faced several problems while integrating new versions. First, I can not append my new build to the older one which worked pretty fine. Second, I build xcode project with into fresh folder, and change few project settings: added new frameworks, enabled Obj C exceptions, added compiler flag(as mentioned in SDK integration guide - I added -fobjc-arc flag) to all the Mopub Sdk files. Now when I try to append the new build to this project, The append button is disabled. So I have to make fresh build and make all the settings again to pass the builds. Can you please clarify which setting affected the 'append button'? Any sort of help would be appreciated.

Thanks. PS: I cloned the recent Mopub SDK from master branch.