public function setSiteAliasUrls($idSite, $urls = array())
    {
        Piwik::checkUserHasAdminAccess($idSite);

        $mainUrl = Site::getMainUrlFor($idSite);
        array_unshift($urls, $mainUrl);

        $urlsProperty = new Urls($idSite);
        $urlsProperty->setValue($urls);
        $urlsProperty->save();

        $inserted = array_diff($urlsProperty->getValue(), $urls);

        $this->postUpdateWebsite($idSite);

        return count($inserted);
    }