It seems that the toplevel (default) namespace is not generated for each class - to get things put in a namespace, you have to put it into a UML sub- package.
Could be wrong, but that's the only way I've got this to go, so far. You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com.
