It seems that Microsoft decided that those who wish to have Windows 7 Starter edition will need to forget everything about customization.
Not only that you will not be able to change sounds and cursors, but not being able to change wallpaper? C'mon Microsoft, is this really necessary?
Only hope is in independent wallpaper changing programs (I always recommend Wallpaper Cycler). I surely hope that they will have some workaround available.