Ok, first of all, thnx for helping!
Hmm,I'm not sure if I understand it correctly. So first I (smooth) bind geometry (like arm) to the skeleton (joints). Then you say I use Blendshape muscle shapes to drive the skin. Can you just shortly explain a bit this part? What exactly do you mean by "blendshape muscle"? How do I do this? And when I apply wrap deformer, do I select the skin and then only the object, that will represent muscle object and apply wrap?

Tnx again for help, and sorry, but I'm a still a noob when it comes to animation.

--edited--
ok, I just cant figure out how to attach muscle to the bones.
here another link:
link

You see first picture? How do I do that the muscle is somehow conected to the bones, so if you move bones, the muscle will move also?


--edited #2--
Ok, I've solved the problem with parenting. Instead of ordinary parent I had to use constraint parent.