In a saucepan of boiling water, cook green and yellow beans and soy beans for 3 minutes, drain well and rinse under cold water to chill. Cut green and yellow beans into 2 inch (5 cm) pieces. Set bean mixture aside.
Meanwhile, in a large bowl, combine chickpeas, celery, green onions and red pepper. Add bean mixture to bowl.
In a small bowl, whisk together vinegar, mustard, oil and pepper. Pour over bean mixture and toss to coat. Add basil and parsley and toss again.