Open coconuts by first removing most of husk near pointed top. Then, using a heavy cleaver, crack top of coconut with the bottom corner of the blade. Using the edge, pry the coconut open just enough to pour out the water into a small bowl. Once empty, lay coconut on its side and slice across through the open slit to completely expose the inside. Scrape soft, white flesh out completely. Put all ingredients except berries in a high-powered blender and blend until smooth, scraping sides often. Slice berries if they are large. In tall glasses, alternate layers of berries and mousse until full. Serve immediately, or chill overnight to set (mousse will be as firm as ice cream).