Making a rendered video with a transparent background

I have no problems rendering a video, but when the render is complete, the exploded view I've rendered explodes through the ground and isn't visible again until it moves back up through the ground. This isn't a problem I have when saving an unrendered .avi file. What settings should I change to make it so the rendered video has a transparent background? (I'm using a student edition of 2014)

SolidworksPhotoview 360