Vista doesn't have themes per se although the syntax is supported. Vista lets users choose window chrome basically but not a full theme as far as I can tell - the only thing that changes by the user settings is the actual window border, not the content.
Vista always uses the default grey theme. So if you had an app before that used Luna on XP it will show grey just the same. So I would say theming for things like toolbars per OS is dead.
However, if you're building tools like your's you should probably provide common themes with preset colors like the Office 2003/blue theme, or maybe the Office 2007 black or blue themes etc. but those color values will need to be hardcoded as opposed to coming from the OS.
+++ Rick ---
>Hi for all!
>
>I'm working on a new Outlook2003Bar version and have a problem to choose the correct theme when using Windows Vista.
>
>It seems like Office 2007 doesn't use predefined themes based on Windows Vista active theme like Office 2003 does with Windows XP.
>
>It seems that you can choose between the 3 different Office themes independently of Windows Vista active theme.
>
>Is this right or am I missing something?
>PS: I don't have Windows Vista nor Office 2007 to test, I only saw some demo videos...