QtDeclarative does not handle translations for imported modules

Currently in qml the translation feature is built-in in qmlviewer, which installs the translation file passed as argument. You need to pass all qml files that have tr strings when generating the translation, .qm file (add support for qmlproject to lupdate?). As we provide more complex components, we will need to be able to internationalize the plugin components imported from qml (avoid redoing the translation every time the component is used).