Configure StatePrinter to only follow the declared types?

I'm using Stateprinter to print/compare my types. It works quite nicely, however, it does compare the actual type of each (sub) object instead of the declared type of the subobject.

An example:

class X {
  string Foo;
  int Bar;
}

interface IMyData {
  public X MyConfig { get; }
}

Now, when calling:

var cfg = ConfigurationHelper.GetStandardConfiguration();
cfg.Add(new PublicFieldsAndPropertiesHarvester());
var printer = new Stateprinter(cfg);

// ...

IMyData v = new MyDataWithMoreStuff();

printer.PrintObject(v);

This will print all the public fields and properties of MyDataWithMoreStuff instead of only the public state visible via IMyData.

Is there a way to do this with Stateprinter, or if that is currently not implemented, is it even possible using C# reflection to walk the "member tree" of an arbitrary object and treat the fields not by the concrete types that they have at runtime, but by the (base / interface) types the variables are declared with?