camshaft:
Peter :You need either speaker link or Powerlink and a new missus.
Edited Peter's response to make it more accurate
Well, she was almost right - actually they are "out of space 1989" 
Must have been radical back then, but I have to admit that the Pentas look somewhat 90s today. Still, just the other day I gawked at them and the Beogram 6000 from a new angle, and if you imagine the copper stripe to be teak, they actually blend quite well...
Steve, I've seen the cables on eBay every now and then, but as they are strictly B&O, I don't imagine that many get sold without the speakers they attach to so it may be a long search. But it's worth asking the dealer, I believe they don't charge that much for just relatively simple cables.