"type not defined" exception with WF4 RC

I`m gettin the following exception while invoking my workflow (dynamically):

The following errors were encountered while processing the workflow tree: 'DynamicActivity': The private implementation of activity '1: DynamicActivity' has the following validation error: Compiler error(s) encountered processing expression "TryCast(simplerule_out,OutputBase2)". Type 'OutputBase2' is not defined.

'DynamicActivity': The private implementation of activity '1: DynamicActivity' has the following validation error: Compiler error(s) encountered processing expression "Res". Type 'OutputBase2' is not defined.

'DynamicActivity': The private implementation of activity '1: DynamicActivity' has the following validation error: Compiler error(s) encountered processing expression "Res". Type 'OutputBase2' is not defined.

'DynamicActivity': The private implementation of activity '1: DynamicActivity' has the following validation error: Compiler error(s) encountered processing expression "New List(Of OutputBase2)". Type 'OutputBase2' is not defined.

The workflow is very simple and worked fine on VS 2010 beta 2!

All I`m trying to do is to create new list of my abstract custom type "OutputBase2".

public class OutputBase2
{
    public OutputBase2() { }

    public bool Succeeded { get; set; }
}

class Example
{
    public void Exec()
    {
        ActivityBuilder builder = new ActivityBuilder();
        builder.Name = "act1";
        var res = new DynamicActivityProperty { Name = "Res", Type = typeof(OutArgument<List<OutputBase2>>), Value = new OutArgument<List<OutputBase2>>() };
        builder.Properties.Add(res);
        builder.Implementation = new Sequence();
        ((Sequence)builder.Implementation).Activities.Add(new Assign<List<OutputBase2>> { To = new VisualBasicReference<List<OutputBase2>> { ExpressionText = res.Name }, Value = new VisualBasicValue<List<OutputBase2>>("New List(Of OutputBase2)") });
        Activity act = getActivity(builder);

        var res2 = WorkflowInvoker.Invoke(act);
    }

    string getXamlStringFromActivityBuilder(ActivityBuilder activityBuilder)
    {
        string xamlString;
        StringBuilder stringBuilder = new StringBuilder();
        System.IO.StringWriter stringWriter = new System.IO.StringWriter(stringBuilder);
        System.Xaml.XamlSchemaContext xamlSchemaContext = new System.Xaml.XamlSchemaContext();
        System.Xaml.XamlXmlWriter xamlXmlWriter = new System.Xaml.XamlXmlWriter(stringWriter, xamlSchemaContext);
        System.Xaml.XamlWriter xamlWriter = System.Activities.XamlIntegration.ActivityXamlServices.CreateBuilderWriter(xamlXmlWriter);
        System.Xaml.XamlServices.Save(xamlWriter, activityBuilder);
        xamlString = stringBuilder.ToString();
        return xamlString;
    }

    public Activity getActivity(ActivityBuilder t)
    {
        string xamlString = getXamlStringFromActivityBuilder(t);
        System.IO.StringReader stringReader = new System.IO.StringReader(xamlString);
        Activity activity = System.Activities.XamlIntegration.A开发者_StackOverflow中文版ctivityXamlServices.Load(stringReader);
        return activity;
    }
}

Thanks!

---

The solution is to add the 'VisualBasicSettings' instance while executing the activity.

This thread was useful:
http://social.msdn.microsoft.com/Forums/en-US/wfprerelease/thread/2b77771e-84a6-4ec3-a944-3de2a60201fc