ESS labels on ESMTP mail: perhaps using Net::Server::Mail::ESMTP

[clyde.ingram]

I am searching for a method to generate ESMTP e-mails with ESS
labels. The Perl module Net::Server::Mail::ESMTP - "A module to
implement the ESMTP protocole", by Olivier Poitrey <[email protected]>
on CPAN, looks like a possibility.

However the documentation and source code do not seem to mention ESS
labels.

Does anyone know whether I can use this or any other library to
generate e-mails with ESS labels?

Thank-you,
Clyde