gistfile1.txt

        public class BTPinchGestureRecognizer : UIPinchGestureRecognizer
	{
		
		public BTPinchGestureRecognizer(NSObject target, Selector action) : base(target, action) 
		{
			ShouldReceiveTouch  += (sender, touch) => {
				//if (touch.View is UISlider || touch.View is MPVolumeView) return false;
				return true;
			};
			
		}
	}

        public class OverviewDialogViewController : DialogViewController
	{
		public OverviewDialogViewController () : base()
		{
			Style = UITableViewStyle.Plain;
		}
		
		public override void LoadView ()
		{
			base.LoadView ();
			//setup stuff

//most likely you can just use a UIPinchGestureRecognizer not the custom one... I was using custom for swipes....
			TableView.AddGestureRecognizer(new BTPinchGestureRecognizer(this, new Selector("pinch")));
				

and the pinch handler:
                [Export("pinch")]
		public void Pinch(UIPinchGestureRecognizer sender)
		{
			if (sender.State == UIGestureRecognizerState.Ended)
			{
				SystemSound.Vibrate.PlaySystemSound();
			
		
			}
		}