How do you publish an App Store application in mul

Question

I've got an Windows 8.1 (Modern UI) Application that has support for French and Spanish. If I set the OS language to French or Spanish and run my application in the debugger, the application appears to find the correct language resource dlls and runs in the desired language. I've recently published my application (in English only) to the App Store. When I go to my test machine, change the language to Spanish, download the application from the store, I get English. Same thing happens if I set the OS language to French. Is there some trick to packaging the bundle before I publish or do I need to go to the Dev Center and add French and Spanish in the Submission to publish?

Edit: In the package manifest, I've added the section:

  <Resources>
    <Resource Language="en" />
    <Resource Language="es" />
    <Resource Language="fr" />
  </Resources>

And I've add Spanish (es) and French (fr) Languages to the Submission to the Dev Center. Still, when I load the app from the App Store onto a Spanish Windows 10 Session, I'm still only seeing the English string constants.