Green field in a videobox

I bought a red curtain roll up effect video from Shutterstock and the area in the videobox that is not yet covered by the curtain is green (during the effect). My problem is that I can not find any way to replace the green with the background behind it. When I bought the videobox I thought that it ofcourse must be transparent but it´s damn solid. Very strange because it´s pretty meanless to see this bright green parts instead of an image behind it. So I wonder if you can use coding to change that? I also wonder if you can code it to not roll the curtain backward when it has moved it down the whole way? Here you have a screenshot of the bastard: