Heat oven to 180°C (170°C for dark or nonstick pan). Grease or spray bottom only of 13x23cm pan.
In large bowl, beat cake mix, reserved pineapple juice, water, oil and eggs on low speed 2 minutes, scraping bowl occasionally (do not overbeat); stir in 2 teaspoons orange peel. Pour into pan.
Bake as directed on box for 13x23cm pan. Run knife around sides of pan to loosen cake. Cool completely, about 1 hour.
In medium bowl, stir together frosting, pineapple, coconut and 2 teaspoons orange peel. Spread frosting mixture over top of cake. Garnish with additional coconut and strawberries. Store loosely covered.