Preheat oven to 350 F. Grease and flour 3 round layer pans. Beat egg whites until stiff. In another bowl, cream butter and sugar. Add egg yolks. Remove 2 Tbs. Melted white chocolate and reserve for icing; add remaining chocolate to butter-egg mixture. Mix well. Sift flour, baking pwd., and salt together and add to batter. Add buttermilk, pecans, vanilla and coconut. Gently fold in egg whites. Divide evenly among 3 cake pans, and bake 30 mins. Or until cake springs back when pressed. Cool. Icing: In top of double boiler ove medium heat, beat together: 1/2 cup softened butter, 6 ozs. Cream cheese and 2 Tbs. Reserved melted white chocolate. Add 1 tsp. Vanilla extract and 1 pound powdered sugar, mixing until smooth. Fold in 1 cup chopped pecans. Spread warm frosting on cooled cake layers. Serve immediately or store in refrigerator; let warm to room temp. Before serving.