send-hook and forward_format

[Alexandre]

Hi,
I want to set forward_format when I send mail to XXX.

Then, my muttrc should be something like this:
send-hook ^.*XXX.*$     'set forward_format="[TAG] %s"'

But my forward_format is still like this:
set forward_format="[%a: %s]"
(actually in results of my tests.)

How do you customize this ?

Thank you for advices.
-- 
Alexandre Delanoë