在App_Code文件夹中将类组织到命名空间不能按预期工作

I have a couple of classes that I have created for my web project and I am going to store them in the App_Code folder. I don't want to store all the classes in the top level (no namespace) but want to organize them into namespaces. So far this does not seem possible because when I use the "using XXXX;" namespace statement it still can't find the right class in my code behind files. What could I be doing incorrectly?I have a couple of classes that I have created