The mask editor is a huge help for keying. It means that the greenscreen does not have to fill the background, or we can get rid of unwanted foreground objects. I've been working with the same test footage I had before, and have almost figured things out. Here's a screenshot of my node setup: (Click for larger)
It's not simple, I think I'm doing something wrong, and I get some weird artifacts (see red arrow) and an outline of the mask. I'm getting there though, the rod and flags in the foreground are gone!
Here's a good page about the mask editor: http://wiki.blender.org/index.php/User:Nazg-gul/MaskEditor



