Realistic Reflections with Objects that have strange angles

So I can do a reflection in Corel fine, as long as the bottom edge is straight and flat.  I work for a beer distributor, and I want to know how I can reflect some of the packages realistically.  The angles are strange, so if you just mirror it down it looks funny.  Check out this picture:


I want it to look like the bottom one, but ya know, upside down.  If I just mirror it it looks like the middle one.  Thanks in advance for any help :)