Video Transparency in Storyline

Currently, I can place an image on a timeline and then place a video "above" it.  I can animate the video to fade in so that the image shows through for a time before becoming fully non-transparent and blocking the image.  Since the code seems already built to fade/make transparent a video, can a setting be added that allows the video fade int to be frozen at a certain point so it remains transparent for the entire slide?