public function createRequest($messageName, RequestOptionsInterface $params)
    {
        $this->checkMessageIsInWsdl($messageName);

        $builder = $this->findBuilderForMessage($messageName);

        if ($builder instanceof ConvertInterface) {
            return $builder->convert($params, $this->getActiveVersionFor($messageName));
        } else {
            throw new \RuntimeException('No builder found for message '.$messageName);
        }
    }