The last thing to do here is joining the eye-bones to the biped. To do this, select each of the eye-bones in turn, and click the 'link' button. Now make sure you clearly click and drag on the eye-bone, and you should see a dotted-line extend from the pivot point. Drag this line to the head bone (you may have to hide the head mesh). Now open the selection box, select the head bone, and click 'Link'.
3DSMax8 will not update the biped tree until you go into selection mode, open the selection box, close it again, and reopen it. Do this and check that the structure has been updated as below:
