/**
  * Upgrade a Quotation to an order
  * by Quotation number and returns the
  * ID of the order
  * @param  integer $no
  * @return integer      return the ID of the Order
  */
 public function upgrade($no)
 {
     $handle = $this->getHandle($no);
     return $this->client->Quotation_UpgradeToOrder(array('quotationHandle' => $handle))->Quotation_UpgradeToOrderResult;
 }