What they don't tell you
I have looked at this for a little while and still can't seem to get it to work as I would like it to.
I found my wallpapers were cropped while rotating screens.
With the launcher and the wizardii wallpaper I set the landscape wallpaper while the device is in portrait mode and use set Stretch Landscape.
Using a static wallpaper and the scroll off.
It still appears to crop a little but you will have a full screen image in Landscape and portrait modes (like the 5 native wallpapers when you use the default wallpaper settings).