public static ModelNode AddSilverlightWebPart(this ModelNode model, SilverlightWebPartDefinition definition, Action<ModelNode> action)
 {
     return model.AddDefinitionNode(definition, action);
 }
 public static ModelNode AddSilverlightWebPart(this ModelNode model, SilverlightWebPartDefinition definition)
 {
     return AddSilverlightWebPart(model, definition, null);
 }