XData: Use Delphi Interface based model for JSON serialisation

I am currently evaluating xdata to expose data and functionality of a delphi desktop application to the web.The application does not use Aurelius, but some selfmade ORM mechanisms and quite some model classes which are designed as interfaces and built on top of some S4D features (especially Spring.Collections, Nullable). What would you recommend to wire something like this most efficiently to XData? Currently if I e.g. try to expose entities as interface instances via XData it fails, because rtti cannot properly handle interface instances.
Currently it appears as if I would have to

Moving this to the support category as this is not a feature request.

I think the best idea is your second option, which is build wrapper/transfer (DTO) objects for using in XData.

That's a good approach even if you use Aurelius or if you use objects instead of interfaces, because it separates your layers, having specific objects for your API. This gives you freedom to evolve your API separately from your model/db layer.