The disclaimer seem to only be added to the plain text version of the email, and does not show up when email is viewed as html (which is pretty standard nowadays).
I think altermime can do this as well, but have not been able to get it to work. I tried a quick hack by editing /etc/amavis/conf.d/50-user and set @altermime_args_disclaimer to user --disclaimer-html instead of --disclaimer but that removed the disclaimer completely, so I'm probably missing something.

Is there a simple way to make it modify the html version of email as well?

Thanks,
Peter

EDIT: Please disregard. I tried the same thing again, and now it works. Must have made a typo before. However, after playing a little, would it be possible to make the @altermime_args_disclaimer setting read

@altermime_args_disclaimer = qw(--disclaimer=/etc/postfix/disclaimer/_OPTION_.txt --disclaimer-html=/etc/postfix/disclaimer/_OPTION_.html);

instead?  This way both are possible, and we can create different version for plain text and html formatted email... Maybe an idea for the 0.6.0 release