aca20031 is talking about errors that the compiler will throw when you try to use RenX classes in code due to the compiler not being able to see the Renx code. This works for UDK classes because the UDK does in fact come with full source to all the unreal script classes.
To work around this all you need to do is implement the prototypes of what you need from each class you are working with. The actual code in the "RenX" files you compile doesn't have to do anything. They are just needed to prevent the compiler from throwing the errors.
