Removing startup project in a VSPackage

Hi,

I'm looking for a way to remove the start project of a visual studio solution with a VSPackage (so that not project at all is set as start project of a solution). The following code doesnot work:

IVsSolutionBuildManager buildManager = (IVsSolutionBuildManager)GetService(typeof(SVsSolutionBuildManager));
buildManager.set_StartupProject(null);

Any idea how to get it done?

Best regards,

Dimitri