[Mimedefang] auth_authen macro not visible in mimedefang

[murthy]

Hello all,
   I am trying to capture the auth_authen macro in mimedefang. The
%SendmailMacros has values for things like daemon_name, if_addr,
mail_addr etc but not for auth_authen.

My sendmail configuration for Milter is as below

O Milter.macros.connect=j, _, {daemon_name}, {if_name}, {if_addr}
O Milter.macros.helo={tls_version}, {cipher}, {cipher_bits},
{cert_subject}, {cert_issuer}
O Milter.macros.envfrom=i, {auth_type},
{auth_authen},{auth_ssf},{auth_author},{mail_mailer},{mail_host},{mail_addr}
O Milter.macros.envrcpt={rcpt_mailer}, {rcpt_host}, {rcpt_addr}
O Milter.macros.eom={msg_id}

And I am running mimedefang with option '-a auth_authen'.

Still the macro value does not appear. I have tested that my sendmail
daemon asks user authentication properly. Please help me.

regards
murthy