Soak the mung bean threads (also called cellophane noodles) in hot water for twenty minutes. Drain, and cut into 5 cm lengths. Set aside. * Split the carrots, celery and leeks lengthwise in half. Clean, peel, and slice the vegetables into 1 cm-thick slices. Melt the butter in a stockpot over medium-high heat. Add the onions, carrots, leeks, parsley, garlic, bay leaves and juniper berries, tossing the mixture well to coat with butter. When the vegetables begin to sizzle, reduce the heat to medium low and cover. Cook, covered, stirring occasionally, about 10 minutes. Add the tomato to the stockpot and stir for 1 minute. Add the fish bones and trimmings and white wine. Cook this mixture for 5 minutes, stirring occasionally. Add cold water to cover and raise heat to medium high. Bring to a boil, skimming all of the froth from the surface as it forms. Immediately lower heat and simmer gently, uncovered, for 35 to 40 minutes. Strain the mixture, pressing the solids firmly to extract all liquid. Discard the solids. Add salt to taste. Heat 4 cups fish broth in a saucepan. Steam clams separately in small amount of broth just until shells open, removing each shell as it opens. Transfer to 4 warm soup bowls; strain clam broth into warm fish broth, avoiding any grit at the bottom. Add oysters to fish broth and cook gently over low heat, uncovered, just until edges curl, about 1 minute. Place 2 oysters in each bowl. Ladle warm broth into bowls and add 2 tablespoons mung bean threads. Add radicchio leaves and saffron and serve.