the best way to create a shadow from where he would be standing is as follows.
Create a plane, ideally the exact same size and shape as the top of the shelf, but realistically it can be just about any size. Then right click, and assign a new material that says "use background". The plane itself won't render, just any shadows (or relfections, if you want those - default is .5 reflectivity). It also won't show up in the alphamap, cept for shadowing stuff....
And that's it!