see http://dev.plone.org/ticket/12413
Yep, confirmed. The API doesn't support 'reply-to'.
The zope2 project on Launchpad has been archived at the request of the Zope developers (see https://answers.launchpad.net/launchpad/+question/683589 and https://answers.launchpad.net/launchpad/+question/685285). If this bug is still relevant, please refile it at https://github.com/zopefoundation/zope2.
Bug watches keep track of this bug in other bug trackers.
Yep, confirmed. The API doesn't support 'reply-to'.