Please provide a sample project that reproduces the problem. You should call RegisterEntity for all classes in all units that you want to use from Aurelius. You should also have the class flagged with the model [Entities]. To avoid confusion, you should prepend TPerson reference with the unit name where it belongs to:
Person := fManager.Find<Entities.TPerson>(1);
And this is not related to the improvement you mentioned, that one refers to having classes with same name in the same model. Here we're talking about different models.