Following Francois Ripault's comment, I am studying OCamlDoc's custom
tags.  (Thank you Francois!)  I implemented the attached custom
generator implementing @en and @ja tags together with a new command
line option "-lang".  Now, what I want to do is:

ocamlfind ocamldoc -package lablgtk2.gnomecanvas -g custom.cmxs -d html -lang ja file.ml ...

However, since ocamlfind does not recognize -lang as a proper option
for ocamldoc, I get:

ocamldoc: unknown option `-lang'.

Is there any way to tell ocamlfind to pass the '-lang ja' option as is
to ocamldoc?  Alternatively, how do I specify the equivalent of
'-package lablgtk2.gnomecanvas' without using ocamlfind?  I tried:

ocamldoc -I lablgtk2.gnomecanvas     -g custom.cmxs -d html -lang ja file.ml ...
ocamldoc -I +lablgtk2.gnomecanvas    -g custom.cmxs -d html -lang ja file.ml ...
ocamldoc -I +lablgtk2                -g custom.cmxs -d html -lang ja file.ml ...

etc., but they all produced:

Error: Unbound class GnoCanvas.group

Thank you in advance.

Sincerely,

-- 
Kenichi Asai