我在iphone iOS 4项目中使用了three20。我无法将项目编译到设备

I try to compile but it fails because it find a duplicated definition of class in one of the dependencies and in the main dependency. I googled a lot and i even found the cause of this, due to a bug in xcode and the optimization for amr6 and arm7 code. But i could't found how to solve this. Has anybody use the three20 library with iOS4 ?I try to compile but it fails because it find a