AFNetworking + download images in queue + cancel operations

I need to download a queue of images.
I created my operations first, then add them with the "enqueue" method of AFNetworking.

I have 2 problems :
1) I didn't have the progress bar working for the queue (and I have it working with a custom operation queue)
2) I didn't find the solution to stop the queue when I want

I created first operations to batch and add theme in a array:

  while ((dict = [enumerator nextObject]))
  {    
    NSMutableURLRequest *request = [[MyHTTPClient sharedClient] requestWithMethod:@"GET" path:@"ws/webapp/services/pull_image" parameters:dict];

    AFImageRequestOperation *operation = [AFImageRequestOperation imageRequestOperationWithRequest:request
imageProcessingBlock:nil                                                                                       cacheName:nil
    success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) 
    {
      NSLog(@"image : %@", [image description]);
      // process images
    }
    failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error)
    {
      // manage errors
    }];

    [operations addObject:operation];
  }

Then, I enqueue the operations:

     [[MyHTTPClient sharedClient] enqueueBatchOfHTTPRequestOperations:operations 
       progressBlock:^(NSUInteger numberOfCompletedOperations, NSUInteger totalNumberOfOperations) 
       {
           float percentDone = ((float)((int)numberOfCompletedOperations) / (float)((int)totalNumberOfOperations));
  [delegate syncServicesController:self updateProgressView:percentDone];
       } 
       completionBlock:^(NSArray *operations) 
      {
        //
      }];

So, the progress download didn't work.
But I can see the progress of numberOfCompletedOperations… ? 1,2,3,4,5… Does I need to force the refresh of the progress view in the main thread ?

And when I tried to stop the network tasks:

- (void)cancelAllRequests
{
  [[MyHTTPClient sharedClient] cancelAllHTTPOperationsWithMethod:@"GET" path:@"ws/webapp/services/pull_image"];

}

I don't understand how to stop the queue of requests… This seems that works but I have this error : -[NSBlockOperation request]: unrecognized selector sent to instance 0x16f54c70