"pumpkin Pie" Filling for Mexico

I live in Chapala, Jalisco, Mexico and canned pumpkin is rather expensive as it is imported. I have worked out what I believe to be a rather good substitute. I usually for go the crust and bake it as a custard of sorts. Where do I get the brown sugar cooked camotes??? From the guy with the wheelbarrow on the plaza in Chapala or sometimes in the arcade there is a lady selling them. You will notice there is no sugar added..... that's how sweet these camotes are.

• Ready In: 1 hr 10 mins
• Yields: 3 pies

Ingredients

• 1 1⁄2 kg  cooked sweet potatoes (camotes cooked in brown sugar)
• 1 1⁄2 liters  Mexican crema
• 2  cups milk
• 8  eggs, lightly beaten
• 1⁄2 teaspoon salt
• 1  tablespoon ground ginger
• 1  tablespoon ground cinnamon
• 1⁄2 teaspoon ground allspice
• 1  teaspoon ground nutmeg
• 1  teaspoon ground cloves
• 3  tablespoons powdered sugar
• 1  teaspoon vanilla
• 4  tablespoons dark rum

Directions

1. Using an egg beater or food processor pure the camotes and their syrup until smooth. Beat in the Mexican Crema, milk, eggs, and spices. Taste and adjust seasonings.
2. If making pies with will make a minimum of 3 deep dish pies. Bake as you normally would for a pumpkin pie.
3. If without a crust bake at 350 degrees for 60 minutes or until a knife inserted in the center comes out clean.
4. Whip the remaining half liter of Crema with vanilla, powdered sugar, and rum until thickened.