The fluxbox site, you can find my theme on this too
My configuration app version 0.9.9.)
HOWTO: Just change your config then press "save".
For now you need to "restart" fluxbox to apply changes.
When you are satisfied press "Let fluxbox change the conf" and "Quit".
HOWTO: Press "Add" to add an entry, then fill the needed stuff
If you want to remove some entry just let the key entry blank (the first one after modifiers)
Press "Save" to save your work then you only need to "reconfigure" fluxbox.