It can work with the Penta speakers -but not with full information in the displays of the speakers.
You can connect with normal 2-pin DIN-speakerplugs. (no info in display)
Then you can use Speaker-link -a 3-pin plug, which is quite rare -but I think you can buy it in a B&O store. As far as I know, it should show source in the display, but not volume/sound settings etc.
To get full display info, you'll need a system with Power-link sockets (such as system 3500/4500, 6500/7000 or BeoCenter 9500/9300 or later models such as 2300/2500/ouverture etc.)