Cook the potatoes in lightly salted boiling water for 25-30 minutes, or until soft when pierced with a fork. Meanwhile, measure the soy milk, olive oil, and garlic into a pot. Sprinkle with salt and pepper. Place over low heat and cook, just below a simmer, for about 15 minutes to soften the garlic, while the potatoes cook. Remove from the heat and set aside while the potatoes continue cooking.