I have an edited video ready to burn. I have checked the "Span" box for multiple disc burning. The video is continuous (no linking was required) with many trims added. The total time is 3:44:29 and it was created by editing a previous video that was also continuous. I want to span this across 2 discs,t the "Split Movie" button does not appear. I have registered the product and the box says it is the "Plus" version; the widow ID also indicates "Plus". Why no button?