IMAP on Mail app Mac OS X Trash folder problems

IMAP on Mail app Mac OS X Trash folder problems

Hi,

I've set up a business account which I intend to use with a Desktop client via IMAP.

I'm on Mac OS X 10.9 (Mavericks) using the default Mac OS X Mail app, and having problems with trashing emails.

Every time I delete an email from the client, after the client syncs again with the server, the message appears again. I selected the Trash folder in Mail, and set it up with the "use as Trash Mailbox" so when I delete an email it's sent there. But it doesn't work. When I delete an email with the "del" key, it reappears.

However, when I move it manually to the Trash folder, seems to work.

Do you know how to configure the client so deletion works by default?

Thanks