Mix crumbs, 1/4 cup of the sugar and the butter; press firmly onto bottom of 9-inch springform pan.
Sprinkle gelatine over 1/4 cup of the water in small saucepan; let stand 1 min. Cook on low heat 3 min. or until gelatine is completely dissolved, stirring constantly.
Beat cream cheese, remaining 1 cup sugar and the cocoa in large bowl with electric mixer on medium speed until well blended. Gradually add gelatine mixture, remaining 1/4 cup water and the liqueur; refrigerate until slightly thickened. Gently stir in the whipped topping; pour over crust. Refrigerate several hours or until firm. Top with chocolate curls just before serving. Store in refrigerator.
