Object(Symfony\Component\Form\Form).data.plainPassword = null

ProfileAdminController.php

<?php

namespace UserBundle\Controller\Admin;

use Symfony\Component\DependencyInjection\ContainerAware;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\Security\Core\Exception\AccessDeniedException;
use FOS\UserBundle\Model\UserInterface;
use FOS\UserBundle\Controller\ProfileController as BaseController;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;

/**
 * @Route("admin")
 */
class ProfileAdminController extends BaseController {

    /**
     * Edit the ADMIN user
     * @Route("/edit-admin-profile", name="edit_admin_profile")
     * @Method({"GET", "POST"})
     */
    public function editAction() {
        $user = $this->container->get('security.context')->getToken()->getUser();
        if (!is_object($user) || !$user instanceof UserInterface) {
            throw new AccessDeniedException('This user does not have access to this section.');
        }

        $class = $this->container->getParameter('fos_user.model.user.class');

        $form = $this->container->get('form.factory')
                ->create(new \UserBundle\Form\Admin\ProfileAdminFormType($class));

        $formHandler = $this->getFormHandler($form);

        $process = $formHandler->process($user);

        if ($process) {
            $this->setFlash('fos_user_success', 'profile.flash.updated');

            return new RedirectResponse($this->getRedirectionUrl($user));
        }

        return $this->container->get('templating')->renderResponse(
                        'admin/Profile/edit.html.' . $this->container->getParameter('fos_user.template.engine')
                        , array('form' => $form->createView())
        );
    }

    /**
     * @param string $action
     * @param string $value
     */
    protected function setFlash($action, $value) {
        $this->container->get('session')->getFlashBag()->set($action, $value);
    }

    protected function getFormHandler($form) {

        return new \UserBundle\Form\Handler\ProfileAdminFormHandler(
                $form, $this->container->get('request')
                , $this->container->get('fos_user.user_manager')
        );
    }

}

ProfileAdminFormHandler.php

<?php

namespace UserBundle\Form\Handler;

use FOS\UserBundle\Model\UserInterface;
use FOS\UserBundle\Model\UserManagerInterface;
use Symfony\Component\Form\FormInterface;
use Symfony\Component\HttpFoundation\Request;

class ProfileAdminFormHandler {

    protected $request;
    protected $userManager;
    protected $form;

    public function __construct(FormInterface $form, Request $request, UserManagerInterface $userManager) {
        $this->form = $form;
        $this->request = $request;
        $this->userManager = $userManager;
    }

    public function process(UserInterface $user) {
        $this->form->setData($user);
       
        if ('POST' === $this->request->getMethod()) {
            
            $this->form->bind($this->request);

            if ($this->form->isValid()) {
                $this->onSuccess($user);

                return true;
            }

            // Reloads the user to reset its username. This is needed when the
            // username or password have been changed to avoid issues with the
            // security layer.
            $this->userManager->reloadUser($user);
        }

        return false;
    }

    protected function onSuccess(UserInterface $user) {
        $this->userManager->updateUser($user);
    }

}

ProfileAdminFormType.php

<?php

namespace UserBundle\Form\Admin;

use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use FOS\UserBundle\Form\Type\ProfileFormType;
use UserBundle\Form\AdminProfileType;

class ProfileAdminFormType extends ProfileFormType {

    public function buildForm(FormBuilderInterface $builder, array $options) {
        parent::buildForm($builder, $options);
        $builder
                ->add('enabled')
                ->add('adminProfile', new AdminProfileType())
        ;
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver) {
        parent::setDefaultOptions($resolver);
        $resolver->setDefaults(['translation_domain' => 'FOSUserBundle']);
    }

    public function getName() {
        return 'admin_profile';
    }

}

ProfileFormType.php

<?php

/*
 * This file is part of the FOSUserBundle package.
 *
 * (c) FriendsOfSymfony <http://friendsofsymfony.github.com/>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace FOS\UserBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use Symfony\Component\Security\Core\Validator\Constraint\UserPassword as OldUserPassword;
use Symfony\Component\Security\Core\Validator\Constraints\UserPassword;

class ProfileFormType extends AbstractType
{
    private $class;

    /**
     * @param string $class The User class name
     */
    public function __construct($class)
    {
        $this->class = $class;
    }

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        if (class_exists('Symfony\Component\Security\Core\Validator\Constraints\UserPassword')) {
            $constraint = new UserPassword();
        } else {
            // Symfony 2.1 support with the old constraint class
            $constraint = new OldUserPassword();
        }

        $this->buildUserForm($builder, $options);

        $builder->add('current_password', 'password', array(
            'label' => 'form.current_password',
            'translation_domain' => 'FOSUserBundle',
            'mapped' => false,
            'constraints' => $constraint,
        ));
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => $this->class,
            'intention'  => 'profile',
        ));
    }

    public function getName()
    {
        return 'fos_user_profile';
    }

    /**
     * Builds the embedded form representing the user.
     *
     * @param FormBuilderInterface $builder
     * @param array                $options
     */
    protected function buildUserForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('username', null, array('label' => 'form.username', 'translation_domain' => 'FOSUserBundle'))
            ->add('email', 'email', array('label' => 'form.email', 'translation_domain' => 'FOSUserBundle'))
        ;
    }
}

J'utilise "friendsofsymfony/user-bundle": "~1.3",