Auto forward emails with appended text

Question

Does anyone know of a free webmail or email client for Windows, that allows you to auto-forward incoming mail to another email address AND at the same time, add some predefined text to the body of the forwarded message?

EXPLANATION OF WHY (in case someone can suggest a better avenue of investigation):

I am trying - by a very roundabout method - to setup Posting By Email to a Wordpress site. My client has no control over their server environment (internal politics) so I believe I am limited, in the short term at least, to using Jetpack's Post By Email module. The reason for this is that Jetpack will generate an email address to use straight away, which allows me to work on the problem immediately, rather than having to wait for my client's internal IT department to install php-imap on their server, setup an email address and perhaps some cron jobs etc etc

The problem is that Jetpack has no options for changing the default Status and Publicize settings of posts sent by email. By default posts are published immediately and broadcast via email, Facebook and Twitter - not what we want! The options can be changed by including shortcodes in the email body. But the target users of the system are likely to be of low IT competency, so it is undesirable to require they use shortcodes - I would rather the shortcodes were added automatically. So, I was thinking if I could use a free webmail account, setup auto-forwarding to the Post By Email address given to me by Jetpack, and have the shortcodes appended to the email just as it is forwarded, that would be - loosely speaking - a viable solution... but I can't find an email client that will do it. Any suggestions?

Answer 1

How about a custom email signature that contains the shortcodes? (like [publicize off] and [status draft)

Whenever they send an email to the post by email address they should also choose a specific signature.