A simple hack to issue https://github.com/sonata-project/SonataFormatterBundle/issues/19 Data is stored in content instead of rawContent.

FormatterBlockService.php

<?php

/*
 * This file is part of the Sonata project.
 *
 * (c) Thomas Rabaix <thomas.rabaix@sonata-project.org>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Application\Sonata\FormatterBundle\Block;

use Sonata\FormatterBundle\SonataFormatterBundle;
use Symfony\Component\HttpFoundation\Response;

use Sonata\AdminBundle\Form\FormMapper;
use Sonata\AdminBundle\Validator\ErrorElement;

use Sonata\BlockBundle\Model\BlockInterface;
use Sonata\BlockBundle\Block\BaseBlockService;
use Sonata\FormatterBundle\Block\FormatterBlockService as BaseFormatterBlockService;

/**
 * In order to keep data in textarea, data will be stored in content (not rawContent).
 * For more information see issue: https://github.com/sonata-project/SonataFormatterBundle/issues/19
 * 
 * @author Marc Juchli <mj@codag.ch>
 */
class FormatterBlockService extends BaseFormatterBlockService
{
    /**
     * {@inheritdoc}
     */
    public function buildEditForm(FormMapper $formMapper, BlockInterface $block)
    {
        $formMapper->add('settings', 'sonata_type_immutable_array', array(
            'keys' => array(
                array('format', 'sonata_formatter_type_selector', array(
                    'source' => 'content',
                    'target' => '[content]',
                    'listener' => true,
                )),
                array('content', 'textarea', array()),
            )
        ));
    }

    public function getParent()
    {
        return 'Formatter';
    }
}