Once you have successfully deployed the certificates to the users, each user must configure his or her e-mail application to use the e-mail certificates for S/MIME protection. The following sections detail how to enable S/MIME security in:
Microsoft Office Outlook
Outlook Web Access (OWA)
S/MIME is available only in the OWA provided with Exchange Server 2003 and Exchange Server 2007. Previous versions of OWA do not provide support for S/MIME protection.
Outlook 2003 and Outlook 2007 automatically use available e-mail signing and encryption certificates if the certificates exist in the user’s profile.