Windows 7: Theme Question - Modify Theme In Place

Hello,
I have a theme that I am always adding new wallpapers to...

The default behavior when I modify a theme and select new wallpapers is that it creates a new theme named "Unsaved Theme" and retains the original theme unmodified...



Is there any way to change this behavior so that it modifies the theme in place? It is tedious to always be deleting and renaming the theme back.

For example, I have a theme named "Rainforest" with a green taskbar and am frequently adding new rainforest-esque wallpapers to this theme... When I checkmark new images to be included in the shuffle, it creates a new theme "Unsaved Theme". I would like to be able to add the wallpapers without having to save a new theme and delete the old theme... there would only ever be one "Rainforest" theme.

I hope I am clear.

Thank you.
Patrick