Straight swap, Kind of, you will need the B12 axle and torque arm. The axle is only because it must fit the adjusters on the swingarm and is slightly longer. The torque arm mounts further up the arm on the B12 than the B6, so you will need the longer arm from the B12.
I know this from experience, as my bike has gone through quite a transformation including the swingarm. I had a good tire on my B6 wheel and wanted to wear it out before switching over to the B12 wheel and tire and those items listed above were the only problems I found.
HTH
Josh