Animation Issues

I have a little problem, I have a webcontrol viewcontroller and some button, I want to apply curl animation to webview and see instad webview view if the same controller.

like this

instead of this

in the first case, I use webview.hidden = YES, but when I try to return to the (obviusly) hidde view, if I put webview.hidden = NO in the method to return, I get this

any solution?

this is my code:

- (IBAction)toggleView:(id)sender {


    CATransition *animation = [CATransition animation];
    [animation setDelegate:self.view];
    [animation setDuration:0.7];
    [animation setTimingFunction:UIViewAnimationCurveEaseInOut];

    animation.type = @"pageCurl";
    animation.fillMode = kCAFillModeForwards;
    animation.endProgress = 0.7;

    [animation setRemovedOnCompletion:NO];
    [[self.vistaWeb layer] addAnimation:animation forKey:@"pageCurlAnimation"];

}

- (IBAction) torna {

    CATransition *animation = [CATransition animation];
    [animation setDelegate:self.view];
    [animation setDuration:0.7];
    [animation setTimingFunction:UIViewAnimationCurveEaseInOut];

    animation.type = @"pageCurl";
    animation.fillMode = kCAFillModeBackwards;
    animation.startProgress = 0.7;
    animation.endProgress = 0;

    [animation setRemovedOnCompletion:NO];  
    [[self.vistaWeb layer] addAnimation:animation forKey:@"pageCurlAnimation"];
}