First, make sure you're using Poser 5 or above: P4 and Pro Pack don't support ray-traced reflections.
 
Next, go to the Material Room and select the "mirror" material on the Veepster.
Next, apply a reflection node. Here's a tutorial on my website: How to Make Reflections in Poser 5 (and above).
After that, check your Render Options: make sure you use the Firefly Renderer (the P4 Renderer doesn't support ray-traced reflections). Also make sure you use at least 3 or 4 ray-trace "bounces": more is better, but the more bounces, the longer the scene will take to render.
 
--John

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