i also got wallpaper to work using background for all...install the 1921 version unless u have an old version of the rom.
http://forum.xda-developers.com/showthread.php?t=584978
then you can change your wallpaper to whatever u want and it will display on all tabs.
edit: the mod changes the tab wallpaper on world clock, and settings tab as well...just an FYI.