[O] new exporter: remove postamble in html of export subtree

[Alan Schmitt]

Hello,

I'm trying to remove the postamble in the html-export of a subtree, and
I don't know how to do it. This is what I tried:

#+BEGIN_SRC org
:PROPERTIES:
:EXPORT_OPTIONS: html-postamble:nil
:END:
#+END_SRC

(I found the name of the option in the org-e-html.el file.)

How can I specify this option so that it only applies to a subtree?

Thanks a lot,

Alan