Peter :
You are in luck! B&O have just brought out a converter for this - you do need a DC power source as well. The Beolab 3s connect to the BL2 and the computer connects to the BL2.
Rather than finding out through a post reply in a thread, surely this - and similar news - should be on both the Beoworld homepage, as a news story, and a more detailed article for members?
All the Beoworld 'news' these days is prizes, competition winners and how great Beoworld has become ;)