STIR Crust Mix, sugar, margarine and water with fork in 9-inch pie plate until crumbs are well moistened. First press firmly against side of pie plate, using finger or measuring cup to shape edge. Press remaining crumbs firmly onto bottom, using measuring cup.
MICROWAVE chocolates in 2 separate small microwaveable bowls on HIGH 1 min. or until chocolates are almost melted. Stir until chocolates are completely melted; cool slightly.
BEAT milk and Filling Mix with mixer on low speed until blended. Beat on medium speed 3 min. (Filling will be thick.) Slowly stir half the filling mixture into each bowl of melted chocolate. Spoon semi-sweet chocolate cheesecake mixture into crust. Top evenly with white chocolate mixture. Refrigerate at least 1 hour.