Talk:Thornmail/@comment-67.169.207.175-20110207061701

I have a friend who's been doing a lot of calculations with Thornmail and, in the process, has come to the realization of just how ridiculous it is when against physical DPS-ers. But he has a question that I haven't found the answer to anywhere: does Thornmail's returned damage stack with magic penetration? Can I get a Void Staff and then expect a 40% magic penetration with Thornmail's returned damage?