I'd like to use bash completion in zsh for a script with

complete -C 'tu --get-bash-completion' tu

'tu --get-bash-completion' is invoked by zsh completion, but the three
arguments bash would pass to it aren't being passed.

Is there another config option I need to know about, or is this behavior
not implemented?

Question also here:
http://stackoverflow.com/questions/19662649/using-bash-complete-c-in-zsh

Thanks,

Tom