Drain liquid from pineapple chunks and sweet potatoes into 2 litre microwavable pan. Peel Kiwi fruit, cut into quarters, length-wise, and slice thinly. Cut pineapple chunks into quarters. Add brown sugar and corn starch to liquid in pan; mix well. Add butter and raisins. Microwave at 60% for 3 minutes, or until butter is melted; mix well. Add pineapple and Kiwi fruit. Microwave at 80% for 5 minutes. Mix well. Microwave at 80% for 5 minutes more, or until sauce begins to thicken. Add sweet potatoes. Mix well, but gently, so as not to break up potatoes. Microwave at 80% for 5 minutes. Let stand 3 minutes; stir before serving.