Erweiterung einer Extension um ein Feld - create Exception

Hi,
ich habe die Extension pw_comments mit meiner Extension (my_pwcomments) um das Feld Subject erweitert.
Erstellt habe ich meine Extension mit dem Extensionbuilder. Das hat auch wunderbar geklappt und auslesen kann ich mein neues Feld "subject" im Template ganz einfach über {comment.subject}

Mein Typo3 ist das aktuelle 6.2.9

Hier das Mapping in ext_typoscript_setup.txt

config.tx_extbase{
    persistence{
        classes{
            Tx_PwComments_Domain_Model_Comment {
                subclasses {
                    Tx_MyPwcomment_Comment = MyTYPO3\MyPwcomment\Domain\Model\Comment
          	}
            }
            MyTYPO3\MyPwcomment\Domain\Model\Comment {
                mapping {
                    tableName = tx_pwcomments_domain_model_comment
                    recordType = Tx_MyPwcomment_Comment
                }
            }
    	}
    }
}

ext_tables.php

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addStaticFile($_EXTKEY, 'Configuration/TypoScript', 'my pwcomments');

\TYPO3\CMS\Core\Utility\GeneralUtility::loadTCA('tx_pwcomments_domain_model_comment');

if (!isset($GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['ctrl']['type'])) {
	if (file_exists($GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['ctrl']['dynamicConfigFile'])) {
		require_once($GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['ctrl']['dynamicConfigFile']);
	}
	// no type field defined, so we define it here. This will only happen the first time the extension is installed!!
	$GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['ctrl']['type'] = 'tx_extbase_type';
	$tempColumns = array();
	$tempColumns[$GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['ctrl']['type']] = array(
		'exclude' => 1,
		'label'   => 'LLL:EXT:my_pwcomment/Resources/Private/Language/locallang_db.xml:tx_mypwcomment.tx_extbase_type',
		'config' => array(
			'type' => 'select',
			'items' => array(),
			'size' => 1,
			'maxitems' => 1,
		)
	);
	\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addTCAcolumns('tx_pwcomments_domain_model_comment', $tempColumns, 1);
}

$tmp_my_pwcomment_columns = array(
    'subject' => array(
        'exclude' => 1,
        'label' => 'LLL:EXT:my_pwcomment/Resources/Private/Language/locallang_db.xml:tx_mypwcomment_domain_model_comment.subject',
        'config' => array(
            'type' => 'input',
            'size' => 30,
            'eval' => 'trim'
        ),
    ),
);

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addTCAcolumns(
    'tx_pwcomments_domain_model_comment', 
    $tmp_my_pwcomment_columns
);

$GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['types']['Tx_MyPwcomment_Comment']['showitem'] = $TCA['tx_pwcomments_domain_model_comment']['types']['1']['showitem'];
$GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['types']['Tx_MyPwcomment_Comment']['showitem'] .= ',--div--;LLL:EXT:my_pwcomment/Resources/Private/Language/locallang_db.xml:tx_mypwcomment_domain_model_comment,';
$GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['types']['Tx_MyPwcomment_Comment']['showitem'] .= 'subject';

$GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['columns'][$TCA['tx_pwcomments_domain_model_comment']['ctrl']['type']]['config']['items'][] = array('LLL:EXT:my_pwcomment/Resources/Private/Language/locallang_db.xml:tx_pwcomments_domain_model_comment.tx_extbase_type.Tx_MyPwcomment_Comment','Tx_MyPwcomment_Comment');

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes(
    'tx_pwcomments_domain_model_comment', 
    $GLOBALS['TCA']['tx_pwcomments_domain_model_comment']['ctrl']['type'],
    '',
    'after:' . $TCA['tx_pwcomments_domain_model_comment']['ctrl']['label']
);

Das Model:

namespace MyTYPO3\MyPwcomment\Domain\Model;


/**
 * Comment
 */
class Comment extends \Tx_PwComments_Domain_Model_Comment {

	/**
	 * subject
	 *
	 * @var string
	 */
	protected $subject = '';

	/**
	 * Returns the subject
	 *
	 * @return string $subject
	 */
	public function getSubject() {
		return $this->subject;
	}

	/**
	 * Sets the subject
	 *
	 * @param string $subject
	 * @return void
	 */
	public function setSubject($subject) {
		$this->subject = $subject;
	}

}

ich habe dann in constants und setup noch definiert das die templates aus meiner extension gelesen werden sollen

plugin.tx_pwcomments {
    view {
        templateRootPath = {$plugin.tx_pwcomments.view.templateRootPath}
        partialRootPath = {$plugin.tx_pwcomments.view.partialRootPath}
        layoutRootPath = {$plugin.tx_pwcomments.view.layoutRootPath}
    }
    settings {
        sendMailTemplate = {$plugin.tx_pwcomments.settings.sendMailTemplate}
        sendMailToAuthorAfterSubmitTemplate = {$plugin.tx_pwcomments.settings.sendMailToAuthorAfterSubmitTemplate}
        sendMailToAuthorAfterPublishTemplate = {$plugin.tx_pwcomments.settings.sendMailToAuthorAfterPublishTemplate}
        badWordsList = {$plugin.tx_pwcomments.settings.badWordsList}
    }
}

Ein Problem bekomme ich aber leider beim Speichern:

#1297759968: Exception while property mapping at property path ""😛roperty "subject" was not found in target object of type "Tx_PwComments_Domain_Model_Comment".

Kann mir einer sagen wie das lösen kann, am besten ohne einen eigenen Controller zu schreiben zu müssen 😉

Grüße boOgiE