Oh, if you apply the movie to a "billboard" prop, you might find it useful to make a JPG targeting image -often made using a frame of the movie- in an image map node as a temporary texture while you set up the scene.  This is a targeting image that I use for the pixie dust starburst movie, for example:

This can help a lot to get the movie billboard positioned/scaled properly.  Once you have that done, unplug the targeting guide image map node, and plug the movie node back in. ^^

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5