Hi Ralf,
We have solved this when building a new application framework by using interfaces for both the classes (A) which implement the business logic and also the interface parameters (B) itself. E.g. instead of passing a structure to the methods of (A) we used classes implementing another interface that has setter and getter values (you can have a look at class CL_FPM_PARAMETER from WDA UI as reference for this).
Hope this helps!
Best regards,
Alej