if you render in passes, you can do this very easily in max,
render > render elements > take your pick.
it allows you to ultimate control over you animation, you can easily adjust many things in your animation this way, lighting, shadows, color, adjust spec highlights.. the uses are endless
Rendering in layers give you the same benefits, You render your forground, background, or anything else you want specific control over, on a seperate layer.
To do this, you need photoshop, or a compositing program such as after effects or combustion for PC, or shake for a mac, the software is very expensive, luckily a team member has some of this type of software.
if you need help with this concept, there are plenty of reasorces on the web under "rendering in layers or passes" or email me and I'll do my best to help you out.
riley_ag@attbi.com