QServiceManager loadInterface does not work

QServiceManager loadInterface does not work, I have to use

// QServiceManager from QtMobility API to load xxx plugin
QServiceManager* serviceManager = new QServiceManager();

QList<QtMobility::QServiceInterfaceDescriptor> descriptors =
serviceManager->findInterfaces("xxxxxxxxx");
qDebug()<<descriptors.at(0);
QCoreApplication::addLibraryPath(QCoreApplication::applicationDirPath());
QObject* serviceObject = serviceManager->loadInterface(
descriptors.at(0));

Earlier I was trying to use

// QServiceManager from QtMobility API to load xxx plugin
QServiceManager* serviceManager = new QServiceManager();

qDebug()<<descriptors.at(0);
QCoreApplication::addLibraryPath(QCoreApplication::applicationDirPath());
QObject* serviceObject = serviceManager->loadInterface(
interfaceName);

The plugin/service is getting only if I call the findInterfaces() observed on Maemo