En el codigo del controller he setteado la fecha de creación a la fecha actual:
Código PHP:
    /**
     * Creates a new SchoolRecord entity.
     *
     * @Route("/create", name="admission_school_record_applicant_create")
     * @Method("POST")
     * @Template("ABCAdmissionBundle:Applicant:Applicant.html.twig")
     */
    public function createAction(Request $request)
    {   
        $session = $this->getRequest()->getSession();
        $appId=$session->get('applicant');
            
        $entity = new SchoolRecord();
        $form = $this->createCreateForm($entity);
        $form->handleRequest($request);
        $em = $this->getDoctrine()->getManager("admission");
        $applicantObject = $em->getRepository('ABCAdmissionBundle:Applicant')->find($appId);
        $entity->setApplicant($applicantObject);
        $app=$entity->getApplicant();
        $entity->setCreatedDate(new DateTime());
    //    $entity->setIsCurrent('true');
               
        if ($form->isValid()) {                 
            $em->persist($entity);
            $em->flush();  
            $session = $this->getRequest()->getSession();
            $session->set('step',3);
            $session->set('applicant',$app->getId());
            return $this->redirect($this->generateUrl('admission_applicants'));
        }
            $session->set('step',2);
            $session->set('applicant',$app->getId());
            return $this->redirect($this->generateUrl('admission_applicants'));
       /* return array(
            'entity' => $entity,
            'form'   => $form->createView(),
        );*/
    } 
    Código PHP:
   public function buildForm(FormBuilderInterface $builder, array $options)
    {      
        $builder
            ->add('schoolName','text',array('label'=>'School name - Nombre del colegio *'))
            ->add('fromDate','date',array('format' => 'dd-MMM-yyyy',
                                          'years'=>range((date("Y")-14), date("Y")),
                                          'label'=>'Attended from - Periodo desde'))
            ->add('toDate','date',array('format' => 'dd-MMM-yyyy',
                                          'years'=>range((date("Y")-14), date("Y")),
                                        'label'=>'Attended to - Periodo hasta'))
            ->add('headName','text',array('label'=>'Name of the Head - Nombre del Director'))
            ->add('phoneNumber','text',array('label'=>'Phone number - Teléfono'))
            ->add('eMail','text',array('label'=>'E-mail - Correo electrónico'))
            ->add('isCurrent','choice',array(
        'label'=>'Information of present school - Información del colegio actual *',
        'empty_value' => 'Choose an option',
        'choices'=> array(
            'true' => 'Yes / Si', 
            'false' => 'No',
            )))
           // ->add('createdDate')
            ->add('address','entity',
                 array('label'=>'Select a address *',
                       'class'=>'ABCAdmissionBundle:Addresses',
                       'property'=>'id'
                 ))
        ;
    } 
    Código HTML:
 {% extends "ABCAdmissionBundle::layoutAppForm.html.twig" %}
{% block title %} School Information Form {% endblock %}
{% block contenido %}
{{form_start(form)}}
    {{form_errors(form)}}
    <div class="row-fluid">
        <div class="span12">
            {{form_row(form.schoolName, {'attr': {'class': 'span11'}}) }}
            {{ form_row(form.headName, {'attr': {'class': 'span11'}}) }}
        </div>
    </div>
     <div class="row-fluid">
        <div class="span6">
        {{form_label(form.fromDate)}}    
        {{form_widget(form.fromDate.day,{'attr': {'class': 'span3'}}) }}
        {{form_widget(form.fromDate.month,{'attr': {'class': 'span3'}}) }}
        {{form_widget(form.fromDate.year,{'attr': {'class': 'span3'}}) }}
        {{form_row(form.phoneNumber)}}
        {{form_row(form.address)}}
        </div>
        <div class="span6">
        {{form_label(form.toDate)}}
        {{form_widget(form.toDate.day, {'attr': {'class': 'span3'}}) }}
        {{form_widget(form.toDate.month,{'attr': {'class': 'span3'}}) }}
        {{form_widget(form.toDate.year,{'attr': {'class': 'span3'}}) }}
        {{form_row(form.eMail)}}
        {{form_row(form.isCurrent)}} 
        </div>    
    </div>
{{form_widget(form.save)}}
{{form_end(form)}}
{% endblock %} 
 

