Loading Custom Ribbon.xml in Office 2013 by COM-addins developed for Office 2007.

Hello,

I have created 2 ribbons.xml in an Addin project for an Office 2007 app by VS 2008.

Ribbon1.XML -> is loaded for Office 2007 and the second one, Ribbon2.xml -> is loaded for Office 2013.

In the Ribbon constructor I have done OfficeVersion check and in GetCustomUI(string ribbonID) loading the appropriate ribbon for that Office Version. For Office 2007, its customized ribbon is loaded nicely, but for Office 2013 the customized ribbon is not loading. Below is code where it checks the officeVersion and loads the required ribbon.

public string GetCustomUI(string ribbonID)
{        
   if (pptVersion == 15)
   {
     return GetResourceText("PowerPointAddIn.PowerPointRibbon2013.xml");
   }
   else if (pptVersion == 12)
   {
       return GetResourceText("PowerPointAddIn.PowerPointRibbon2007.xml");
   }
   else
   {
      return GetResourceText("PowerPointAddIn.BasicRibbon.xml");
   }
}

The Office 2013 app is also not showing an error. Is that the correct procedure to load different custom ribbons.xml through 1 single addin built for a different version of Office? 

Regards,

Sayan