原来的答案很简单：从XCode 4.0升级到（至少）XCode 4.0.2它的工作原理像一个魅力。必须是XCode版本中的错误。

Turns out the answer is very simple: Upgrade from XCode 4.0 to (at least) XCode 4.0.2 and it works like a charm. Must be a bug in the XCode version.