Notify designer that property has changed type

I have two classes that use ExpandableObjectConverters to provide properties for controls that expose them as properties.  Lets call these PropertyClassA and PropertyClassB.  If I expose a property as a generic Object call it MyProperties() and return a PropertyClassA the Property grid of the designer will let me see the properties of PropertyClassA.  If I have another property that changes the value that is returned by MyProperties() to a PropertyClassB how do I notify the designer that my property types of changed so that it can refresh its display?

That sounds like a mouthfull and I like examples.  When I toggle the 'TypeA' property of MyCustomControl below the property grid does not reflect the change.  And yes this is a very convoluted example ;-)


<TypeConverter(GetType(ExpandableObjectConverter))> _
public class PropertyClassA
      public property Name as string ...
      public property ClassAValue as string ...
end class

<TypeConverter(GetType(ExpandableObjectConverter))> _
public class PropertyClassB
      public property Name as string ...
      public property ClassBValue as integer ...
end class

public class MyCustomControl
      inherits UserControl
      private myProperties as Object = new PropertyClassA
      public writeonly property TypeA as Boolean
           Set(value as boolean)
                if value then
                   myProperties = new PropertyClassA
                else
                   myProperties = new PropertyClassB
                end if
           End If
      End property
      public property MultiTypeProperties as Object ...
end class