1. Mix lemon juice and soy milk and let sit for 10 minutes. (An easier way to think about the measurement is to pour 1 1/2 tsp lemon juice into a measuring cup and add soy milk until it reaches 1/2 cup.)
2. In a large bowl, whisk together the mayonnaise, lemon juice and soy milk mixture, chives, parsley, dill, garlic powder, onion powder, salt and pepper.
3. Cover and refrigerate for 30 minutes before serving.