无法在xcode中生成iOS应用程序存档

I have a problem generating a iOS App archive from an application. The application compiles just fine and even works in the simulator. Now I wanted to make som ad hoc testing and cannot generate the iOS App Archive. When I click on the Product -> Archive it generates a generic xcode archive. Can anyone help me. I should mention, that I have already generated an iOS App Archive of this application. It has just stopped to generate iOS Archive for some reason. Thanks a lot.I have a problem generating a iOS App archive f