public function DoCapture($doCaptureReq, $apiCredential = null)
{
$apiContext = new PPApiContext($this->config);
$handlers = array(new PPMerchantServiceHandler($apiCredential, self::$SDK_NAME, self::$SDK_VERSION));
$this->setStandardParams($doCaptureReq->DoCaptureRequest);
$ret = new DoCaptureResponseType();
$resp = $this->call('PayPalAPIAA', 'DoCapture', $doCaptureReq, $apiContext, $handlers);
$ret->init(PPUtils::xmlToArray($resp));
return $ret;
}