"It cannot be done in Poser." Yes it can. You just have to not rely on the default rigging currently in wide use, which isn't even beginning to tap into the capability of the rigging system available. Aki is still one of the most incredible animated characters ever.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)