Default tab color for selected tabs in Excel w/ Vista
 

We've got many Vista PC's rolled out and a very common complaint is that
there is virtually no difference in color between a selected tab and an
unselected tab in Excel when using Vista's default theme. This is especially
problematic when people are selecting multiple tabs to make group changes.
They will invariably mess up the spreadsheet because they forget they've got
five tabs selected. How can we change this color without forcing everyone to
select the Windows XP theme?

Is there a theme definition we can use that is "professional" that will show
this difference?