Hi Thomas, the name "powerlink" fooled me to when I first came across it.
So no, it does *not* supply the electrical power needed by the ICE amps inside the active speakers; so you will still need to separate power cords.
What the powerlink cable does do, is switch the active speakers from standby mode (their little eyes (sorry LEDs) are glowing red) to active mode (green glow).
There appear to be a number of different Sony models that match the term '46" Sony Bravia XBR' so can you provide a precise model number ? The reason I am asking is that active speakers with their own buil-in amplifiers should *not* be coupled to say a 20W output.
Also the Sony seems to have its own built-in speakers (e.g. the 20W reference) how do you intend to "disable" them, or are they to be the centre speaker ?
First B&O (1976) was a Beogram 1500 ... latest (2011) change has been to couple the BL11 with the BL6Ks *sounds superb*