I'm in an environment where all incoming and outgoing email (messages sent within exchange exempt) need to be forced into plain text. I'd like to do this at the Exchange level if possible. Client side is a mix up of iphone/pad and OWA and ~3 Outlook 2007 clients using OutlookAnywhere so a client side fix would be hard to enforce.
I've looked at Transport rules, but do not see any Transport Rule Actions that seem to be relevant. Perhaps there is something I do not know.
Google is not proving too helpful, or maybe I am searching for the wrong things. Perhaps a 3rd party application?