the bearings can not work from the b14 to b15 unfortunately. the bearing width is different, the b15 is a wider bearing and wont fit in the knuckle from the b14 correctly.
I think the ultimate solution is to get the b15 brakes and see how they hold up with your wheels. If they don't fit, you have to get new wheels. But overall the setup would be much simpler.
I'm converting the whole suspension to b15 stuff to aid me later on when I need replacement parts. but buying new wheels/tires isn't going to be cheap.