How to get product IDs in the shopping cart in the shipping selection page?

[smallpotato]

I am trying to get product IDs in the shopping cart in the shipping selection page editting tpl_checkout_shipping_default.php like the shopping cart page (tpl_shopping_cart_default.php).

I added the following code in tpl_checkout_shipping_default.php, but I just got "NULL" information.
I might have to use some session functions? Please tell me how to fix the issue.

<?php
  $productArray[$i] = array('attributeHiddenField'=>$attributeHiddenField,
  'flagStockCheck'=>$flagStockCheck,
  'flagShowFixedQuantity'=>$showFixedQuantity,
  'linkProductsImage'=>$linkProductsImage,
  'linkProductsName'=>$linkProductsName,
  'productsImage'=>$productsImage,
  'productsName'=>$productsName,
  'showFixedQuantity'=>$showFixedQuantity,
  'showFixedQuantityAmount'=>$showFixedQuantityAmount,
  'showMinUnits'=>$showMinUnits,
  'quantityField'=>$quantityField,
  'buttonUpdate'=>$buttonUpdate,
  'productsPrice'=>$productsPriceTotal,
  'productsPriceEach'=>$productsPriceEach,
  'rowClass'=>$rowClass,
  'buttonDelete'=>$buttonDelete,
  'checkBoxDelete'=>$checkBoxDelete,
  'id'=>$products[$i]['id'],
  'attributes'=>$attrArray);
?>
<?php var_dump($productArray);  ?>