当其中一个类型被更改时，如何转换Typed DataSet Scheme？

I got a typed (not connected) dataset, and many records (binary seriliazed) created with this dataset. I've added a property to one of the types, and I want to convert the old records with the new data set. I know how to load them: providing custom binder for the BinaryFormatter with the old schema dll. The question is how can I convert objects of the old type to objects of the new type - both types has the same name but the new one has one more property.I got a typed (not connected) dataset, and many