You're right about the surround sound, but the rest will be easy. You'll need a length om MasterLink cable to connect the Overture to the Avant. Attach the BeoLab 6000's to the Avant (don't worry, the sockets'll be there), put the Avant in V. Opt 2, and the Overture in A.Opt 1.
I confess that I am really only fully familiar with the US products, and all of our Avants have the Surround module installed. But I have an MX as well, and the set-up described ought to work just fine.
Russ
We kid because we love.
Bang & Olufsen Tysons Galleria
McLean, VA USA