How to set Webobject Video to background? (Captivate 9 Mac)

On a slide is a webobject including a video (streamed from an external hoster). Now I want to add an roll over object, but  the video stays always in the foreground. The roll over object opens in the background behind the video. I found a hint to edit the AdobeCaptivate.ini, but I am working with iOS version.