Encryptor functions are constrained by iOS so it submitting secure e-mails tothe message composition form of the built-in iOS mail app.
Nevertheless Symantec Mobile Encryption for iOS is able to decrypt PGP-EML, PGP/MIMEand PGPPartitioned encoded e-mail.
Reply may be sent either in PGP-EML or PGPPartitioned format, depending on policy and the encoding preferences of the recipient keys.
Application cannot send PGP/MIMEencoded messages due to IOS limitations (one of the reasons for this limitation is unavailability of mail headers for modification)