Usually, at least on gingerbread, it is enough to restart the launcher, adequate has a setting for that, to apply the wallpaper. You probably need to use quickpic to set it.
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tapatalked from GalaxyS
The reboot works works with golauncher ex and launcher pro but not adw. The only difference I can see is that it look like Adwlauncher works with honeycomb because it doesn't have the little expand arrows like the others do. SO my guess is that it acts more like the default vizio launcher which prevents a background image. This sucks because its the best launcher of the three.
I feel your pain I can't stand the black wallpaper for widgets so I've settle on go launcher ex. If we ever get root again we can work around it maybe.