Well, your amplifiers are in the speakers, which means that factor is out of the equation.
Since the BV8 doesn't have a surround module, you're then left with choosing the best path from the dvd/cd-player to the speakers, which means that you should run the TV sound (from your STB) to the BC2, and connect your speakers to it -- and I do believe that your BC2 processes surround, which is another reason for doing that.
I'd still do it if it was connected to a BS3200, for instance. And in your case I'd try to see if it was possible to use the BV8 speakers as center speakers - but maybe someone else here has advice on how to do that.