// add a new interface:
    public interface IExchangeItemDecoratorFactory
    {
        IIdentifiable[] GetAvailableOutputDecorators(IOutputItem decoratedItem, IInputItem targetItem);
        IOutputItemDecorator CreateOutputItemDecorator(IIdentifiable decoratorId, IOutputItem decoratedItem, IInputItem targetItem);

        IDescribable GetDecoratorDescription(IIdentifiable id);
    }

    // add the following methods to the ILinkableComponent:
    public interface ILinkableComponent
    {
        ...

        IExchangeItemDecoratorFactory GetDecoratorFactory();

        void AddOutputItemDecorator(IOutputItemDecorator decorator);

        void RemoveOutputItemDecorator(IOutputItemDecorator decorator);
    }