Hi Jack,

Please find attached a sample that demonstrates how to add styles for any controls you want to add to the theme pack.  You need to provide your own ResourceSet for the style group you want to add this way the application knows where to look for your styles.  In my sample I created a ResourceSet called Microsoft that I would use for all MS controls.  This resource set provides the means for locating the xaml file containing the my styles and providing it to the application.  In order to create this resource set I needed to create a class that derived from ResourceSet<> and implement it.  All this can be seen in my sample.

Let me know if you have any questions.