Imap Sent Items Folder


Don’t know if anyone can help me.
I use windows mail as my email client on a Windows 7 OS.
I recently transferred to this new computer but I have accidentally downloaded all my sent item messages to a backup folder on an external drive.

Is there anyway to transfer all these messages back to Dreamhost’s imap server ‘Sent Items’ folder. I would like to achieve this as I would like to see all my sent messages when I log on at different computers.

Any help would be appreciated.
Thanks very much

I don’t use windows mail but I do use outlook and I have the ability to just select all in a folder and move the messages to a server folder. If you can’t figure out how to use windows mail to do that, you might get the 30 day trial version of outlook just to make the move, or perhaps thunderbird.