Customizing the remix app

When a user goes to create a remix, a default movie loads in with video clips and images already in the clips library as well as audio clips under the soundtrack tab. The two issues I have are that the storyboard is already filled with these clips and under the soundtrack section the audio from the video clips is listed as soundtrack options. How do I clear both of these out like they've done with the Heroes remix?

I also want to disable the ability to add additional video and/or audio clips. Can you do this via a flashvar or other code or do you have to rebuild the remix app?