Preheat oven to 400 Fahrenheit.
Wash the yams and make some holes on the skin, using a folk. Wrap them with aluminum foil. Place the yams in the oven and bake for 40-60 minutes, or until they are soft. Cool the yams for 10-15 min. (BAKING is the key. Baked yams are much sweeter and softer.)
Peel the baked yams and mash with a potato masher.
Mix in the soymilk slowly until the desirable texture. Add molasses and sugar. (I usually taste to see if it is enough sugar)
Mix in pumpkin pie spice. Taste the filling and adjust the sugar or spice if needed.
Stir in the egg replacer and a pinch of salt.
Pour the filling into the pie crust. Even the surface, and bake for 10 minutes (400F).
Lower the temperature to 350F and bake for 50-60 minutes.
Let it cool.