Just use a servo such as this:
http://www.sussex-model-centre.co.uk/B305%5FServo-4834.htmhttp://www.sussex-model-centre.co.uk...Servo-4834.htm

That is what the white cross represents. You will also need one of these on each servo:
http://www.sussex-model-centre.co.uk/FS%2D1%5FFailsafe%5FUnit-1402.htmhttp://www.sussex-model-centre.co.uk...FUnit-1402.htm
Also available from:
http://www.technobots.co.uk/index.html?target=dept_229.html&lang=en-gbhttp://www.technobots.co.uk/index.ht...tml&lang=en-gb

Regards
Ian