[TYPO3-shop] Extend tt_products is not working

[Georg Ringer]

Hi,

I am usually not that bad with extensions but it is kind of not working 
to extend tt_products. The new fields are not visible in $row. The 
fields are shown in the backend form of a record and the hook is called 
because my print_r is working.

My code
-----------------------
ext_localconf.php
require_once(t3lib_extMgm::extPath($_EXTKEY).'class.tx_rgmediaimages_products.php');

$TYPO3_CONF_VARS['EXTCONF']['tt_products']['extendingTCA'][] = $_EXTKEY;
$TYPO3_CONF_VARS['EXTCONF']['tt_products']['PRODUCT'][] = 
t3lib_extMgm::extPath($_EXTKEY).'class.tx_rgmediaimages_products.php:&tx_rgmediaimages_products';

-----

class.tx_rgmediaimages_products.php

class tx_rgmediaimages_products {

	function getItemMarkerArray (&$pObj, &$markerArray, $item, $catTitle, 
$imageNum, $imageRenderObj, $formInfoArray, $code, $id) {

		$row = $item['rec'];
		print_r($row);
	...

-----------------------

Of course there are the <?php tags and every bracket closed.

What did I miss?

thanks
Georg