In a microwave, melt chips and shortening; stir until smooth. With a small new paint brush, brush white chocolate in a thin layer on the underside of each leaf. Refrigerate until set, about 10 minutes. Apply a second layer of white chocolate; chill for at least 15 minutes or overnight. Gently peel leaf from chocolate
For wreath, chill a 14-in. to 16-in. round serving platter in the freezer for at least 15 minutes. Working quickly, scoop 1-1/2-in. balls of sherbet and arrange in a ring on the platter. Make another ring of sherbet scoops inside the first ring. Arrange a third ring on top of the other rings. If sherbet begins to melt, return platter to the freezer for 5 minutes. Garnish with white chocolate leaves and raspberries.