Custom caliburn.micro splashscreen with shell screen explorer

I am new to WPF and Caliburn.micro and I would like to implement a custom popup screen in a WPF application using Caliburn. I am looking for the correct way to do this using the screen explorer (as I understood this is the best solution).

My Bootstrapper looks like this:

public class AppBootstrapper : BootstrapperBase
    {
        private bool actuallyClosing;
        private CompositionContainer container;        

        public AppBootstrapper()
        {
            Start();
        }

        protected override void Configure()
        {
            container = new CompositionContainer(
                    new AggregateCatalog(AssemblySource.Instance.Select(x => new AssemblyCatalog(x)).OfType<ComposablePartCatalog>())
                );

            var batch = new CompositionBatch();

            batch.AddExportedValue<IWindowManager>(new WindowManager());
            batch.AddExportedValue<IEventAggregator>(new EventAggregator());
            batch.AddExportedValue(container);
            container.Compose(batch);
            Thread.CurrentThread.CurrentCulture = Thread.CurrentThread.CurrentUICulture = new CultureInfo("en-US");
        }

        protected override object GetInstance(Type serviceType, string key)
        {
            string contract = string.IsNullOrEmpty(key) ? AttributedModelServices.GetContractName(serviceType) : key;
            var exports = container.GetExportedValues<object>(contract);

            if (exports.Any()) return exports.First();
            throw new Exception(string.Format("Could not locate any instances of contract {0}.", contract));
        }

        protected override IEnumerable<object> GetAllInstances(Type serviceType)
        {
            return container.GetExportedValues<object>(AttributedModelServices.GetContractName(serviceType));
        }

        protected override void BuildUp(object instance)
        {
            container.SatisfyImportsOnce(instance);
        }

        protected override void OnStartup(object sender, StartupEventArgs e)
        {
            DisplayRootViewFor<ShellViewModel>();
        }
    }

      

        
        
        
      

    

ShellViewModel looks like this: (but I really don't want to see its window)

[Export(typeof(ShellViewModel))]
public class ShellViewModel : Conductor<Screen>
{
    [ImportingConstructor]
    public ShellViewModel()
    {
         ActivateItem(new SplashScreenViewModel());
         int i = 10; // loading ... or do the loading inside the splashscreen ??
         ActivateItem(new MainWindowViewModel());
    }
}

      

        
        
        
      

    

SplashScreenViewModel is pretty simple:

[Export(typeof(SplashScreenViewModel))]
    public class SplashScreenViewModel : Screen
    {
        private string appName;
        private string version;
        private string service;
        private string creator;
        private string copyright;
        private string message;

        [ImportingConstructor]
        public SplashScreenViewModel()
        {
            appName = Assembly.GetEntryAssembly().GetName().Name;
            version = Assembly.GetEntryAssembly().GetName().Version.ToString();
            copyright = "Copyright © corp 2014";
            service = "Department";
            creator = "user - " + Service;
            message = "Loading ...";
        }
    }

      

        
        
        
      

    

And finally, MainWindowViewModel:

[Export(typeof(MainWindowViewModel))]
public class MainWindowViewModel : Screen, IGuardClose
{
    [ImportingConstructor]
    public MainWindowViewModel()
    {
        NetworkUpdate(); // do stuff.
    }
    void IGuardClose.CanClose(Action<bool> callback)
    {
        throw new NotImplementedException();
    }

    void IClose.TryClose()
    {
        throw new NotImplementedException();
    }
}

      

        
        
        
      

    

Right now I'm trying to go a little bit with any approach, but it displays either nothing, only the main window, or just a splash screen, or even an empty view for the shell ...

I would really appreciate some hints on this!

Thanks guys...