1) In a medium saucepan over high heat, bring soymilk to a boil, stirring constantly (about 5 minutes).
2) Add the rice, salt, butter, cinnamon, nutmeg, and sugar and stir to combine. Reduce the heat to low and cover.
3) Cook, covered, for about 45 minutes or until all the liquid has been absorbed. Lift the lid and stir every 15 minutes, covering again tightly each time you remove the lid.
4) After all the liquid has been absorbed, remover the pudding from the heat. Cool to warm, and then serve or place in the refrigerator or chill for at least 2 hours before serving.