Yeah, like stingray said, it’s only opening a file from the export audio in Cubase into Wavelab that’s possible. Not how it used to be pre Cubase 4 (IIRC), where Wavelab could be integrated in a way that after editing there, the edited file was directly showing in the Cubase project.
I think mr roos was referring to me using Cubase and Wavelab at the same time, where Wavelab records my outboard mix while Cubase plays its tracks, both using the same audio interface (not so much legacy at all though…) 