Animate player spine to move where the camera is pointing

Hi!, I have a player with an armature and i cannot figure out how to make the player´s spine rotate vertically accordingly to the camera. I tried to make the camera child of the head bone and instead of rotating the camera, i make the bone rotate but the camera moves with all the player´s animations and that is not what i want, then i tried to rotate both separately but then the gun or the hands of the player moves differently to the camera.

So, what I want is to make the camera moves up and down as well as the spine(and with it the arms bones and the guns, which are child of the spine bone) while keeping the gun or arms at the same position (viewed from the first person camera).
Hope you can help me, and thanks!

 

have you found it out, if you have please help