to use a film burn you actually just have a .mov clip of the burn. you then apply it on the video track above your clip, make sure the scale/aspect ratio match, then apply a Luma Key filter. Once you've applied that, select 'key out darker.' and then you have film burn.
i used to have all of my film burn clips in a folder on mega upload and i was going to send that to you but it looks like it got taken down, sorry man