Heat oven to 350°F. Grease 15x10x1-inch baking pan. Line bottom of pan with waxed paper. Prepare cake batter as directed on package using water. Spoon batter into lined pan.
Bake at 350°F. for 17 to 22 minutes or until golden brown and cracks in cake appear dry.
Meanwhile, place clean towel on work surface. With strainer or sifter, lightly sprinkle powdered sugar evenly onto towel.
Loosen edges of warm cake with spatula; immediately invert cake onto sugared towel. Remove pan and waxed paper. Starting with short side, roll up cake in towel; cool on wire rack for 45 minutes or until completely cool.
Meanwhile, in small bowl, combine condensed milk, lime juice and lime peel; mix well. In large bowl, beat whipping cream until stiff peaks form. Fold condensed milk mixture into whipped cream just until blended. Reserve 1 cup lime mixture for topping. Refrigerate while cake is cooling or until thickened.
To assemble cake, unroll cooled cake, removing towel. Spread remaining lime mixture evenly over cake. Using towel, reroll cake; do not roll towel into cake. If desired, trim ends of roll. Use towel to lift cake roll onto serving platter. Spoon reserved 1 cup lime mixture on top of cake. If desired, garnish with additional whipped cream and lime twists. Store in refrigerator.