Docbook man page: Both short and long option alternative example?

I need help with the Docbook syntax for manual pages.
I'm trying to create a Docbook man page segment for this kind of
--help output but fail miserably:
-------cut-------
  -m, --mode=mode Set the mode of created directories to mode. mode is
symbolic or octal mode as in chmod(1). Relative modes assume an
initial mode of a=rwx.
-------cut-------
Can anyone help me and express this in Docbook/XML, please? I'm stuck
after 10 hours of trial&error. HELP!