ASP.Net C# mailing application (IMAP)

Hi,

I am working on asp.net c# mailing application, which deals IMAP
server.
Its a simple mailing application where user can check mail & send new
mail.
I am able to read all the mail from IMAP and able to show to the user.
But while mail sending, dont know the way to save mail as draft and
save mail to sent mail folder. I think this functionality is related
with SMTP and not with IMAP.
Is there any way to save mail as a draft programmatically?

Anyone has idea about this. Please guide me.

Thanks,
Hemant