Hi I've been tinkering around with the two techniques to modify the ribbon with an MS Word addin (Visual Studio 2010, .NET 3.5), a Microsoft.Office.Tools.Ribbon.OfficeRibbon and Microsoft.Office.Core.IRibbonExtensibility. I was hoping to switch between the two in my addin's CreateRibbonExtensibilityObject, but for some reason it is not called now. The documentation says that if an addin implements CreateRibbonExtensibilityObject that it will be called. When I create a fresh project to test doing this very thing, it works. I'd prefer not to abandon my project as-is. Any ideas? Thank you.