If not using the Windows plugin, you can send SecureMail messages by including "!secure" (without quotes) anywhere in the Subject line of an email. The !secure keyword will be recognized by the SecureMail service in any mix of upper and lower case. It will not be removed before the email is secured and sent.
Example 1
From: Smith, John
To: Doe, Jane
Subject: Research Program (!secure)
In regards to our research program…
Example 2
From: Smith, John
To: Doe, Jane
Subject: !secure message – Research Program
In regards to our research program…