Ok, so I skipped the embedded part and added the modules lang folder in an init module to get Episerver to read all the xml-files in that file.

public void Initialize(InitializationEngine context)
        {
                var localizationService = context.Locate.Advanced.GetInstance<LocalizationService>() as ProviderBasedLocalizationService;
            if (localizationService != null)
            {
                string langFolder = HttpContext.Current.Server.MapPath("~/modules/_protected/My.Plugin/lang");
                if (Directory.Exists(langFolder))
                {
                    var configValues = new NameValueCollection
                                           {
                                               {
                                                   FileXmlLocalizationProvider.PhysicalPathKey,
                                                   langFolder
                                               }
                                           };
                    var localizationProvider = new FileXmlLocalizationProvider();                    
                    localizationProvider.Initialize(Constants.ProviderName, configValues);                    
                    localizationService.Providers.Add(localizationProvider);
                }
            }
        }

And this works just fine and aloows me to easily add more language files if needed.

/Kristoffer