$client = new Bitbang\Http\Clients\CurlClient(); // you will probably need to setup CURLOPT_CAINFO or CURLOPT_SSL_VERIFYPEER
$loader = new Lightools\Xml\XmlLoader();
$finder = new Lightools\Ares\CompanyFinder($client, $loader);

try {
    $company = $finder->find('66872944');

    if ($company === NULL) {
        // not found
    } else {
        echo $company->getVatNumber();
    }

} catch (Lightools\Ares\LookupFailedException $e) {
    // process exception
}