How to get own quote-item-field to order-item?

I want to save custom information in order_item-table. These information where created in cart. So I do it like described in this post.

I have installed the attribute:

$installer->addAttribute('quote_item', 'final_delivery_time', $settings);

$installer->addAttribute('order_item', 'final_delivery_time', $settings);

declare the fieldset in config.xml

<fieldset>
        <sales_convert_quote_item>
            <final_delivery_time>
                <to_order_item>final_delivery_time</to_order_item>
            </final_delivery_time>
        </sales_convert_quote_item>

        <sales_convert_order_item>
            <final_delivery_time>
                <to_quote_item>*</to_quote_item>
                <to_invoice_item>*</to_invoice_item>
                <to_shipment_item>*</to_shipment_item>
                <to_cm_item>*</to_cm_item>
            </final_delivery_time>
        </sales_convert_order_item>
</fieldset>

and some code in cart for example

$oQuote = Mage::getSingleton('checkout/session')->getQuote();
    foreach ( $oQuote->getAllItems() as $_item )
    {
        $orderItemId = $_item->getId();
        $_item->setFinalDeliveryTime('some Value');
        $_item->save();
    }

so I got a quote and I have my field final_delivery_time with this value in the sales_flat_quote_item table

After I place the order in onepage-review, I should also have this field in the sales_flat_order_item table, but there is nothing. In the column stands null. So I need the value of the field saved in the order.