Melt butter in a saute pan, add garlic and cook gently for 1 minutes. Add the sliced shiitake mushrooms and continue cooking over low heat until mushrooms are tender. Add the teriyaki sauce, bring to a boil quickly, and remove from heat. Allow mushrooms to cool to room temperature. In a separate bowl, combine all remaining ingredients and mix well. When mushrooms have cooled, combine with the tomato mixture. Serve at room temperature. Refrigerated, mixture will keep for several days. makes 3 cups.