在构建解决方案时，如何让MSBuild任务生成XML文档?

I have a solution with lots of projects. Each project is configured to generate the XML documentation file when building in Debug-Mode (which is default). That works when I build in Visual Studio 2008. In my build script on my integration server I advise MSBuild to build the whole solution, but it won't generate the documentation files. What can I do?I have a solution with lots of projects. Each p