How to pass options to collection fieldset in form created by form manager?

Question

I have form created/called in controller in this way:

class MyController extends AbstractActionController {
    function IndexAction() {
        $form = $this
                 ->getServiceLocator()
                 ->get('FormElementManager')
                 ->get('MyForm',['option1'=>123);
    }
}

And next - In form i have access to passed options:

class MyForm extends Form implements ServiceLocatorAwareInterface
{
    use ServiceLocatorAwareTrait;

    public function init()
    {
        $option1 = $this->getOption('option1');  // I have here "123" !!!


        $this->add(
            [
                'name'    => 'Child',
                'type'    => 'Zend\Form\Element\Collection',
                'options' => [
                    'label'                  => 'Child',
                    'count'                  => 1,
                    'should_create_template' => true,
                    'allow_add'              => true,
                    'template_placeholder'   => '__placeholder__',
                    'target_element'         => [
                        'type' => 'MyFieldset',
                    ],
                ],
            ]
        );
    }
}

But in fieldset saddly - no:

class MyFieldset extends Fieldset implements ServiceLocatorAwareInterface
{
    use ServiceLocatorAwareTrait;

    public function init()
    {
        $option1 = $this->getOption('option1');  // Empty :(
    }
}

So - how to achieve access to "option1" in fieldset?