I am sending push notification on device which has iOS 5.0.1, but notification is not received on iOS5 device.

If i try to send notification on iOS4.3.3 device, it received on this device.

My server is developed in c# and apple push notification certificate is used in .p12 format.

My code to register the notification is

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    // Override point for customization after application launch.

    // Set the navigation controller as the window's root view controller and display.
    deviceToken = nil;


    self.window.rootViewController = self.navigationController;
    [self.window makeKeyAndVisible];
    [[UIApplication sharedApplication] enabledRemoteNotificationTypes];
    [[UIApplication sharedApplication] registerForRemoteNotificationTypes: UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound | UIRemoteNotificationTypeAlert];


    return YES;
}

- (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)devToken 
{
    UIAlertView *alertView=[[UIAlertView alloc]initWithTitle:@"Succeeded in registering for APNS" message:@"Sucess" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    [alertView show];
    [alertView release];

    deviceToken = [devToken retain];



    NSMutableString *dev = [[NSMutableString alloc] init];

    NSRange r;
    r.length = 1;
    unsigned char c;

    for (int i = 0; i < [deviceToken length]; i++)
    {
        r.location = i;
        [deviceToken getBytes:&c range:r];

        if (c < 10) {
            [dev appendFormat:@"0%x", c];
        }
        else {
            [dev appendFormat:@"%x", c];
        }

    }

    NSUserDefaults *def = [NSUserDefaults standardUserDefaults];

    [def setObject:dev forKey:@"DeviceToken"];

    [def synchronize];

    NSLog(@"Registered for APNS %@\n%@", deviceToken, dev);

    [dev release];

}

- (void)application:(UIApplication *)application didFailToRegisterForRemoteNotificationsWithError:(NSError *)error 
{
    NSLog(@"Failed to register %@", [error localizedDescription]);

    UIAlertView *alertView=[[UIAlertView alloc]initWithTitle:@"FAILED" message:@"Fail" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    [alertView show];
    [alertView release];

    deviceToken = nil;
}

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
{
    NSLog(@"Recieved Remote Notification %@", userInfo);

    NSDictionary *aps = [userInfo objectForKey:@"aps"];
    NSDictionary *alert = [aps objectForKey:@"alert"];
    //NSString *actionLocKey = [alert objectForKey:@"action-loc-key"];
    NSString *body = [alert objectForKey:@"body"];


//  NSMutableArray *viewControllers = [NSMutableArray arrayWithArray:[self.navigationController viewControllers]];
//  
//  if ([viewControllers count] > 2) {
//      NSRange r;
//      r.length = [viewControllers count] - 2;
//      r.location = 2;
//      [viewControllers removeObjectsInRange:r];
//      
//      MapViewController *map = (MapViewController*)[viewControllers objectAtIndex:1];
//      [map askDriver];
//  }
//  
//  [self.navigationController setViewControllers:viewControllers];

//  [viewControllers release];

    //NewBooking,"BookingId",Passenger_latitude,Passenger_longitude,Destination_latitude,Destination_longitude,Distance,Time,comments

    NSArray *arr = [body componentsSeparatedByString:@","];
    if ([arr count]>0) {

        MapViewController *map = (MapViewController*)[[self.navigationController viewControllers] objectAtIndex:1];
        [map askDriver:arr];
        [self.navigationController popToViewController:[[self.navigationController viewControllers] objectAtIndex:1] animated:YES];
    }



    //NSString *sound = [userInfo objectForKey:@"sound"];

    //UIAlertView *alertV = [[UIAlertView alloc] initWithTitle:actionLocKey 
//                                                  message:body delegate:nil 
//                                        cancelButtonTitle:@"Reject" 
//                                        otherButtonTitles:@"Accept", nil];
//  
//  [alertV show];
//  [alertV release];


}

Can anyone help me out with this issue. Why notification received on iOS4.3 device but not on iOS5?

Thank you very much!!! in advance