I prepared the Pad Thai without egg replacement. Since I didn't like dishes with egg before, I have no problem cooking the dish without egg here. If you would like to have a kind of scrambled egg in the recipe, you could prepare scrambled tofu from silken or soft tofu and then fold it in. Here in the USA you can buy vegan scrambled eggs, which you could also use for this. Instead of an egg replacement product, you could just add a little Kala Namak to add an egg taste.