Preheat oven to 350°F. Grease 10 x 4-inch (12-cup) fluted tube cake pan; set aside.
Combine cake mix, corn starch, brown sugar and pumpkin pie spice in a large mixer bowl. Add pumpkin, orange juice, oil and eggs. Beat at low speed until combined, then beat at medium speed 3 minutes. Stir in dates, if desired. Pour into prepared cake pan.
Bake 55 minutes or until cake tester inserted in center comes out clean. Cool in pan on wire rack 15 minutes. Remove from pan and cool completely.
For glaze, beat cream cheese, corn syrup, brown sugar and grated orange peel in a small bowl until smooth. If necessary, add 2 to 3 teaspoons milk or orange juice to make desired consistency. Drizzle over cake. Garnish with additional orange peel.