WebPlus X7: Dont scroll with page header advice

Hi i am updating a website using X7 it has a fixed header which works great i have set anything that scrolls over the header to the back, but my problem is when i put a Youtube video on the page even if i send it to back it still comes over the banner, any advice would be great thank you.
http://client.splitwebdesign.com/level/
i have placed a video on the Getting started page as an example.