protected function fillTransaction(SimpleXMLElement $xml) { $hpsPopulator = new HpsTxnPopulator(); $hpsPopulator->setReturnUrl($this->returnUrl)->setExpiryUrl($this->expiryUrl)->setPageSetId($this->pageSetId); $detailsPopulator = new TxnDetailsPopulator(); $detailsPopulator->setReference($this->reference)->setAmount($this->amount); $hpsPopulator->createElement($xml->addChild('HpsTxn')); $detailsPopulator->createElement($xml->addChild('TxnDetails')); }