Made by be
You will need Kegetys (Download here, comes with very simple instructions)
http://www.kegetys.fi/misc
(It's "SFS mod tool v1.1 for IL-2 Sturmovik Cliffs of Dover")
-Place the "BackgroundsHD" folder in your game folder.
-Create a shortcut for your game in your desktop, now right click, properties, and add " -mod=BackgroundsHD"
EXAMPLE:
"C:\Program Files (x86)\Il2 Cliffs of Dover\Launcher.exe" -mod=BackgroundsHD
Here it is:
http://www.mediafire.com/?4z8mtaswz493v07