Well, it should work with an Avant and a PC2/Beoport but in my case it doesn't! As far as I know it is possible to set up a videomaster (Avant, BV7 etc) with the Beoport as a audiomaster, connected via ML. For sure it won't work in a link-room, but as I can't get any sound out of it I'm not sure whether you get sound from the Avant or from the PL-plugs on the Beoport. And possibly you need an IR-eye on your Beoport for remote control. But it has been reported working!
BS3000 and BS9000 will work, although the elder versions might/will need a s/w upgrade. Ouverture, BS2300 and BS2500 have not been reported working, with or without 1611 convertor.
Bart