When sending E-mails, you need some kind of receipt on what you have sent. If SMTP accounts are used it is possible to put a copy of the mail in the sent box according to the example Send Email and Put Copy in "Sent" Folder . But can be done when pop3 account are used?
It is, of course, possible to send a copy of the mail to own Email account and then maybe manually copy the to the sent box. But are there better solutions?
Maybe Read and Delivery receipts will be useful?
That might be useable, but it is somthing else. When important E-mails are sent I think the sender always need a copy of the sent mail to be able to go back and see what was done.
POP3 is basically a single "folder". It's really only an inbox (and by default messages are deleted as soon as they are downloaded, so it's really only temporary storage). IMAP would be a better choice in this case, otherwise It is up to your program to keep local copies of sent messages (perhaps in a database).
IMAP is absolutely a better choice, but the thing is that customers have old POP3 accounts with a lot of old mails, and I am afraid that problems will occur if I try to change them to IMAP. The best would of course be if Chilkat could put a copy of the sent mail in the sent folder of the local .pst-file, but sending a copy of the mail to the own mail account seems to be the best solution in the current situation.
PST files are a Microsoft proprietary format, so I doubt Chilkat will develop a library to work with them.
Not sure if your language of choice works with ActiveX DLLs or not, but if so, you might want to look into "Outlook Redemption" and Outlook automation in general.
When using a mail client such as Thunderbird, Outlook, etc., usually when an email is sent, a copy is placed in the "Sent" mailbox. That "mailbox" could be a local data store in proprietary format (such as a .pst for Outlook, or whatever type of local files Thunderbird keeps), or it could be a folder in an IMAP "Sent" mailbox. In both cases, the act of saving a copy of the email sent is not a part of the SMTP protocol.
As jpbro correctly said, Chilkat doesn't implement functionality to read/write/modify particular email client data stores (such Outlook .pst's or Thunderbird files). Chilkat generally sticks to implementing publicly well-documented protocols, typically specified by an RFC, rather than proprietary undocumented (or poorly documented) formats.