Peel the sweet potatoes and cook in boiling water until soft. Drain, dry, and mash. Pour the cold water into a saucepan on moderate heat and stir in the sugar. Cook until sugar is dissolved and the liquid is clear, about 8 minutes. Cut the top and bottom of the pineapple, trim off the outer skin and slice flesh into 4 and remove the center core. Place flesh into a blender and puree at high speed. Sieve this mixture into a bowl. Dissolve the gelatin in water. Soak the raisins in rum. Chill the terrine or a square mold.
In a bowl, mix the pineapple with the mashed sweet potatoes. Place the clear syrup in a large pan on high heat and add the pineapple and potato mixture. Reduce the heat to low and let cook down to a very thick custard texture. (Whenever you use fresh pineapple you must heat it to the boil in order to kill the Bromeline content. Bromeline is a great digestive, but it stops gelatin from setting.)
Pour mixture into a chilled terrine or mold and place in the refrigerator to set. When firm and chilled, remove Ate from the refrigerator, unmold and slice. Serve with Camembert cheese surrounded with raisins soaked in rum, and toasted almonds. Can also be served spooned out of the mold like a jam.