I have a forum thread open that explains the issue: http://social.msdn.microsoft.com/Forums/en-US/vcgeneral/thread/0a49bd69-7d54-4da8-9270-117814390154.
I was directed here by a moderator of that forum, so I apologize if this not the correct place to address this. It seems more an issue with MFC than Visual Studio. Also, I am using VS2010...not sure if MFC has changed between the two VS versions.
In a nutshell, the Automatic button on the CMFCRibbonColorButton (and CMFCColorButton) doesn't appear to work correctly. If you specify a color for the Automatic Color (non-system-default color), it is ignored when the Automatic color button is pressed.