Thanks a ton Rob for this!
I just created a new QVW with only the MAP..USING part, to make sure that what I've seen is not an artefact of the demo using both methods.
It seems to work (after first reload one needs to uncheck that setting), still - I am not sure if I understand why one needs to change this. Is this your standard work when you MAP ..USING duals?
Any more hints or ideas?