(De)Serializing interfaces

[nims via Digitalmars-d-learn]

I think interfaces are very powerful and I heavily use them. The 
only problem I have with them is that serializing/deserializing 
them to XML or JSON doesn't seem to work. So far I got to try 
Orange and painlessjson. Using Orange all I got was a lot of 
compiler errors. Painlessjson did compile normally but just 
ignores all interface class members.

This is the code I tried (I apologize for not formatting it, I 
have no idea how to do that):
interface MyInterface {
   int GetA();
}

class Foo: MyInterface {
   int a;
   int GetA() { return a; }
}

// maybe add a class Bar later which implements the same interface

class Foobar {
   MyInterface myBar = new Foo();
}

void main()
{
   // serialize it
}