protected function submitForm(HtmlForm $form, array $values = array(), $submitButton = null)
{
if ($submitButton == null) {
$matches = array_filter($form->getButtons(), function ($b) {
return $b->id == 'next-step';
});
$submitButton = count($matches) > 0 ? current($matches) : null;
}
return parent::submitForm($form, $values, $submitButton);
}
