first turn on the figure s collision detection in the properties tab,(from the hip) then click apply collision settings to children. then select the right hand(sorry, before you select it enable ik for the right or left hand, whatever you select) now turn on collision detection for the document window, and use the parameter dials to move the hand in towards the body(use xtrans dial, and side to side dial cause youll break her wrist...)and youll see that the hand still passes throgh the body. now move it away again and select the translate/pull tool in editing tools bar, and if you use that it will collide with the body and not move through. but i find using the dials easier so it doesnt do me a lot of good. i dont find collision detection to be all that useful, but i only do limited things in poser to use it like you said, make sure all the collision detection things are on, and use the editing tools to make your pose, not the dials