[Users] putting sent messages in imap folder

[Renato]

Hello, I've configured getmail to get via pop mail from my multiple
mail accounts, and then the dovecot IMAP server to distribute it to my
PCs - I connect to it from claws-mail. This works properly (after
quite some time spent hacking).

However, I'd still like to use the smtp provided by my accounts, as I
don't want to setup a private smtp server. So what I have now is:
*1 IMAP account that connects to my dovecot server, with no smtp setup
*1 account for every mail I have, with a fake pop server (cm won't let
me leave it blank) and the smtp server provided by the mail account.

This works if not for one thing: I'd like to have my sent mail, no
matter from which account, finish in my IMAP "Sent" folder. I can't
seem to do this by setting it in Advanced->Put Sent messages because
claws-mail wants a local directory there, not an imap one (and this is
by disegn if I understand correctly - out of curiosity, what's the
reason for this?). 

However if I set sent mail to be put in a local mailbox, I can then
manually move it (by drag and drop) to the imap sent folder, so surely
there must be an automated way of doing this, possibly without adding
other mailboxes than the imap one?

kind regards,
Renato