How to set culture on instances created with reflection

In our LOB-application we implemented a simple plugin-system using reflection. Potential plugin-dlls are scanned for types that implement a certain interface and if found are instantiated using Assembly.CreateInstance(). The instantiated type has a method that returns a FrameworkElement (WPF) for display in the UI.

Our problem: when displayed in the UI, the FrameworkElement will use the default culture for localization.

The apps culture may differ from the OS-culture and is set within the OnStartup()-event of the app, by setting

        CultureInfo info = new CultureInfo(language);
        Thread.CurrentThread.CurrentCulture = info;
        Thread.CurrentThread.CurrentUICulture = info; 

Every directly referenced assembly in the project will happily return correctly localized resources (e.g. error messages from backend or license-service).

How can we apply a specific culture when dynamically loading assemblies/instantiating types using reflection?