The recipe calls for a silicone bomb mold and do not have one. I do have the Wilton metal mini ball pan I was going to try to use. I just don't know it I will have problems getting it out of the metal.
I would probably line the pan with plastic wrap, being sure to leave some hanging over the sides. Once frozen, I'm thinking you should be able to use the plastic wrap to lift your mousse from the pan. HTH!