Are you using stable or development? If you've got (i think) 0.9.6 or later, you can use the remember decorations feature. Turn off decorations on you aterm window (this can be set to a hotkey in the .fluxbox/keys file), Right-click on your aterm toolbar label, select Remember > Decorations. Or you can manually edit .fluxbox/apps:
Code:
[app] (aterm)
[Deco] {0x1c0}
[end]
If you're using fluxbox stable, I don't know what to tell you....that was a long time ago.
