For technical reasons, I'm not using the MFMailComposer to send a mail to some users, but my own web service. Doing this does not leave a track of the sent e-mail to my outbox. Is there a way to place a copy of my message in the outbox programmatically??
Unfortunately you won't be able to artificially insert something in the "Sent Mail" folder (I assume that's what you meant instead of Outbox). This is because MFMailComposer is just a view of the mail client and the Sent Mail folder reflects what is actually sent via your email provider.