I think that there's no reason to bother with those files at all as this will not affect your final work and this will not matter to the users at all.
if you're still annoyed by that as you're designing a Windows7 only visual style, here is what I did (as I only design for Windows 7 for a while now)
Make your Windows 7 skin and then make and add some generic parts for the XP sections, with generic, I mean some design that would work well
with any kind of visual style.
Done, from now on, always use this visual style as base for your future works and only touch the Windows 7 parts.
With this method you will never have to bother with the XP parts but if a user still try to use your visual style on XP,
it will work as the parts are there.
Just a suggestion, of course 
