protected function _checkTemplateBlock($sTemplate, $sBlockName)
    {
        $sTplFile = Registry::getConfig()->getTemplatePath($sTemplate, false);
        if (!$sTplFile || !file_exists($sTplFile)) {
            // check if file is in admin theme
            $sTplFile = Registry::getConfig()->getTemplatePath($sTemplate, true);
            if (!$sTplFile || !file_exists($sTplFile)) {
                return false;
            }
        }

        $sFile = file_get_contents($sTplFile);
        $sBlockNameQuoted = preg_quote($sBlockName, '/');

        return (bool) preg_match('/\[\{\s*block\s+name\s*=\s*([\'"])' . $sBlockNameQuoted . '\1\s*\}\]/is', $sFile);
    }