MS Office apps have an incredible API that lets one execute any command that is accessible from the UI, but inaccessible from the Object Model. Specifically, you can use Execute
There are these:
Office 2007: Lists of Control IDs
Office 2010: Office Fluent User Interface Control Identifiers
Office 2013: Office Fluent User Interface Control Identifiers
And see further http://www.rondebruin.nl/win/s2/win003.htm