The traditional British rice pudding is a baked pudding. I would imagine that when you say creamy, you are looking for something with a loose consistancy. This can be achieved by adding more milk/cream to the rice than stated in the recipe. Alternatively try it in a pan. Add the quantity of rice and sugar that you need to the pan then cover with milk to about 1/2 inch above the rice. bring to the boil, then simer, keeping the milk toped up till the rice is almost cooked. At that point add cream and keep stiring regularly till it reaches the consistancy you want.