Ok, thanks. Meanwhile I have found a way to keep a record of encrypted messages. I write the message on notepad, store it in documents, then encrypt it and delete the unencrypted message. The message can then be attached to an email.
If I send an encrypted email everything works and the email is delivered to the recipient. There is, however, no copy of this mail stored in the "sent" box of my email, neither in Windows Live Mail nor at my email provider when I log in to my account. Can this be changed to have a record of encrypted mails sent? Thanks.