Dear Svenja,
That's great to hear, thanks for informing.
If I got you right you now implemented an association (using the /bobf/if_frw_association interface), right?
This is of course possible. However, I want to point out that this is an implementation in ABAP and thus cannot be executed by other runtimes. If you aim for the very to have the association resolved on the DB (using joins), the implemented association cannot be used.
In this case, it might be more appropriate to follow the composition to the link table (which is modeled) and the foreign-key-based cross-bo-association from there on.
It may even be the case, that SADL supports something like this hopping of associations - but I'm not sure on that.
Cheers,
Oliver