The socalled 'AV' function was used to shift the sound of one system (e.g. a BV) to another system (e.g. an audiomaster).
Pushing the 'AV' button on the BeoLink 1000 (it should be there as a hardbutton) before you push the (?) 'DTV' button (= 'SAT') should shift the sound from the BV7 to the BSystem7000 - if properly set up.
Note: be sure that the converter is the last device to be powered on after the BV and the BSys7000!
However, a much better solution would be to connect the speakers to the BV7 - the handling is much easier then, since it automatically turns on the speakers for, what is needed.
In that case the BV should be in Option 2 and the audiosystem in Option 0.
MM