The Ribbon font in Office 2007 and Office 2010 applications is hard-coded and cannot be changed. You can change the size of the font using Windows appearance settings, but you cannot choose another font.
FontSubstitutes is a Windows setting and it no longer influences Office settings because it was affecting the printing processes. Changing the mapping should only affect the font that is going to print.
In older applications like Office 2003 the system fonts could indeed be used for menu entries but this changed in later versions of Office.
Changing settings from Control Panel – Personalization (Themes, Window Color and Appearance) only affects the size and the color of the text, but not the font.
office 2007 2010 font ribbon subsitute change
Microsoft Office Standard 2007, Microsoft Office Basic 2007, Microsoft Office Home and Student 2007, Microsoft Office Professional 2007, Microsoft Office Enterprise 2007, Microsoft Office Professional Plus 2007, Microsoft Office Standard 2010, Microsoft Office Home and Student 2010, Microsoft Office Home and Business 2010, Microsoft Office Professional 2010, Microsoft Office Professional Plus 2010