code: private function addItemDetails(array &$details, Model\SaleItemInterface $item)
      {
          $total = 0;
  
          if (!($item->isCompound() && !$item->hasPrivateChildren())) {
              $itemResult = $item->getResult();
  
              $details['L_PAYMENTREQUEST_0_NAME' . $this->line] = $item->getTotalQuantity() . 'x ' . $item->getDesignation();
              $details['L_PAYMENTREQUEST_0_NUMBER' . $this->line] = $item->getReference();
              if (!empty($description = $item->getDescription())) {
                  $details['L_PAYMENTREQUEST_0_DESC' . $this->line] = $description;
              }
              $details['L_PAYMENTREQUEST_0_AMT' . $this->line] = $this->format($itemResult->getTotal());
              //$details['L_PAYMENTREQUEST_0_TAXAMT' . $this->line] = $this->format($itemResult->getTax());
              //$details['L_PAYMENTREQUEST_0_ITEMURL' . $this->itemNum] = '';
  
              $total = $itemResult->getTotal();
  
              $this->line++;
          }
  
          foreach ($item->getChildren() as $child) {
              $total += $this->addItemDetails($details, $child);
          }
  
          return $total;
      }
docs: Builds the item details.
  
  @param array                   $details
  @param Model\SaleItemInterface $item
  
  @return float