Dice the pumpkin flesh. Put in a saucepan and bring to a boil along with the pineapple juice. Cook until soft for about 15 minutes. In the meantime, dice the mango meat and mix it with the lime juice. Puree the pumpkin in the pot and add the mango pieces. Stir in the preserving sugar well and bring to the boil while stirring. Simmer for 4 minutes and immediately pour into glasses that have been rinsed with hot water. Let cool while standing upside down.