-segueForUnwindingToViewController: fromViewController: identifier: not being called

I have created a custom segue that presents a view controller inside a container that is very similar with Apple's own modal view controllers (I've implemented it as a UIViewController subclass).

I'm now trying to create a custom unwind segue but there's no way I can get the method -segueForUnwindingToViewController: fromViewController: identifier: to be called.

I've also implemented -viewControllerForUnwindSegueAction: fromViewController: withSender: on my container so I can point to the correct view controller (the one that presented this modal) but then the method that should be asked for my custom unwind segue doesn't get called anywhere.

Right now, the only way for me to dismiss this modal is to do it on the -returned: method.

Did anyone could successfully do this with a custom unwind segue?

EDIT: A little bit more code and context

My unwind view controller is configured in the storyboard, not programatically.

I have these pieces of code related to the unwind segues in my controllers:

PresenterViewController.m

I'm using a custom method to dismiss my custom modals here (-dismissModalViewControllerWithCompletionBlock:).

- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController
                                      fromViewController:(UIViewController *)fromViewController
                                              identifier:(NSString *)identifier {
    return [[MyModalUnwindSegue alloc] initWithIdentifier:identifier
                                                   source:fromViewController
                                              destination:toViewController];
}

-(IBAction)returned:(UIStoryboardSegue *)segue {
    if ([segue.identifier isEqualToString:@"InfoUnwindSegue"]) {
        [self dismissModalViewControllerWithCompletionBlock:^{}];
    }