QNetworkRequest and default SSL configuration

Question

I'm using the following piece of code to make HTTPS requests with a server.

QNetworkRequest request;

//request.setSslConfiguration(QSslConfiguration::defaultConfiguration());
request.setUrl(QUrl("https://www.someurl.com/"));

QNetworkReply *reply = manager->get(request);

Everything seems to be working with my test server, but I would like to know if it is recommended to set the defaultConfiguration (uncomment second line) or does the Network API automatically check all defaultConfigurations when using SSL? And if it checks, does it also do if I add one custom configuration? I mean is it required to append the custom configuration to the list of default configuration, for example:

QSslConfiguration SslConfiguration(QSslConfiguration::defaultConfiguration());

QList<QSslCertificate> certificates = SslConfiguration.caCertificates();
certificates.append(QSslCertificate::fromData(certificate.toAscii(), QSsl::Pem));
SslConfiguration.setCaCertificates(certificates);

request.setSslConfiguration(SslConfiguration);

Edit: I would like to add that I'm working on Symbian platform