AFNetworking with XML format response.

gistfile1.m

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
AFHTTPRequestSerializer * requestSerializer = [AFHTTPRequestSerializer serializer];
AFHTTPResponseSerializer * responseSerializer = [AFHTTPResponseSerializer serializer];

NSString *ua = @"Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25";
[requestSerializer setValue:ua forHTTPHeaderField:@"User-Agent"];
//    [requestSerializer setValue:@"application/xml" forHTTPHeaderField:@"Content-type"];
responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"text/xml", nil];
manager.responseSerializer = responseSerializer;
manager.requestSerializer = requestSerializer;

NSDictionary *parameters = @{@"foo": @"bar"};

[manager POST:@"http://smartkalkyl.se/rateapp.aspx?user=xxxxx&pass=xxxxxx"
   parameters:parameters
      success:^(AFHTTPRequestOperation *operation, id responseObject) {
          NSData * data = (NSData *)responseObject;
          self.fetchedXML = [NSString stringWithCString:[data bytes] encoding:NSISOLatin1StringEncoding];
          NSLog(@"Response string: %@", self.fetchedXML);
      }
      failure:^(AFHTTPRequestOperation *operation, NSError *error) {
          NSLog(@"Error: %@", error);
      }];