<?php
// components/com_virtuemart/themes/default/templates/pages/checkout.thankyou.tpl.php
// after line 24

$order_id = $db->record[0]->order_id;
$order_items = new ps_DB;
$q  = "SELECT * FROM `#__{vm}_order_item` WHERE `order_id`='$order_id'";
$order_items->query($q);

$GLOBALS['GA_ECOMM_ITEMS'] = array();
foreach ($order_items->record as $item) {
    $GLOBALS['GA_ECOMM_ITEMS'][] = array(
        'sku' => $item->order_item_sku,
        'name' => htmlspecialchars($item->order_item_name),
        'category' => '',
        'price' => $item->product_final_price,
        'quantity' => $item->product_quantity,
    );
}

$GLOBALS['GA_ECOMM_TRANS'] = array(
    'id' => $order_id,
    'affiliation' => '',
    'revenue' => $db->record[0]->order_total,
    'shipping' => $db->record[0]->order_shipping,
    'tax' => $db->record[0]->order_tax
);