Is it possible to access and set an emails Information Rights Management using Powershell or EWS when creating a new email externally of outlook?

Hi,

I developed a script to be used within System Centre Service Manager to send emails from an incident.  We are currently building towards ISO270001 accreditation which states that we must catagorise all emails sent as Controlled, Restricted, or Public.

This is being done via the IRM option within the outlook client (using exchange 2010).

Is there any way I can set this information using either EWS or Powershell? 

My current email solution is a powershell script using the system.net.mail.mailmessage object.

Any help is appreciated even if it is a definite 'not possible'

Thanks

Ed (P.S. Sorry if I have the wrong forum)

Ed