Custom class as type in settings

Hi all,

I have switched from Visual Studio to SharpDevelop (I'm using 5.1 build 5071) a few months ago and I'm very happy I did. But there is one thing that annoys me a bit. If I use one of my own classes in settings they show as a ? in the settings editor and they default back to a string when compiling. It seems I can't select one of my own classes at the type of a setting.

As a workaround i now manually change the code in the settings.Designer.cs file every time, but that's a bit annoying. How can I do this correctly?