Looking good!
It seems that you have the molding of part down. MY only concern is that you may have created a undercut in your mold, but im not sure.
@Adam, I like your idea. There are a lot of builder of the ODST armor, maybe we should work thorougher...
@rachciav:
Im using a faom that is used of furnisher. I think its called cold foam over there but im not sure, its really comfortable, not expansive, easy to cut, easy to glue and easy accessible.