[Flow] allow mapping of subproperty

[Alexander Wende]

I have an entity "mitarbeiter" which extends \TYPO3\Party\Domain\Model\Person. My MitarbeiterController works fine but now I have to implement a RestController for "mitarbeiter". The listAction of the RestController works out of the box, but when I try to create a "mitarbeiter", I got "It is not allowed to map property 'firstName'". 
I tried several combination of the propertyMapping Configuration. My Current Rest Controller looks like that:

/**
 * @Flow\Scope("singleton")
 */
class MitarbeiterController extends \TYPO3\Flow\Mvc\Controller\RestController{

    /**
     * @Flow\Inject
     * @var \Company\Project\Domain\Repository\Organisation\MitarbeiterRepository
     */
    protected $mitarbeiterRepository;

    protected $defaultViewObjectName = 'TYPO3\Flow\Mvc\View\JsonView';

    protected $resourceArgumentName = 'mitarbeiter';

    public function listAction(){        #works fine    }

    /**
     * initialize create action
     *
     * @return void
     */
    public function initializeCreateAction() {
        $this->arguments['mitarbeiter']->getPropertyMappingConfiguration()->allowProperties('name','name.firstName','name.lastName');
        $this->arguments['mitarbeiter']->getPropertyMappingConfiguration()->allowCreationForSubProperty('name');
        $this->arguments['mitarbeiter']->getPropertyMappingConfiguration()->allowCreationForSubProperty('name.firstName');
        $this->arguments['mitarbeiter']->getPropertyMappingConfiguration()->allowCreationForSubProperty('name.lastName');
    }

    public function createAction( \Company\Project\Domain\Model\Organisation\Mitarbeiter $mitarbeiter){
        $this->mitarbeiterRepository->add($mitarbeiter);
        $this->response->setStatus(201);
    }


What I am doing wrong?