help with pop3/imap

i'm writing a program that has some email capabilities and am a little stuck right now. I'm trying to figure out how to be able to forward messages without having to download them and then resend. In web based email you can forward emails with attachments without having to download the attachment then reupload it to send the email. But when you are talking to the POP3 mail server you have to download the message and then resend. Is there anyway I can tell the server to forward the message without having to do that. Or is that something POP3 can't do? Is that an IMAP capability? Hope I'm clear enough. Thanks.