how do I transfer my outlook 2007 pop3 mail box into a new Imap account?

I have a folder with emails in outlook 2007. I recently set up a new imap account, and now I would like to ‘upload’ the folder with emails to that imap account. I tried dragging the folder under the root of the imap store in outlook 2007, but the emails just don’t sync or upload to the new and empty imap account on the web server. Anyone know how to tackle this problem?