Sending mail later...?

Is there any way to use the "Send Mail Later" feature to have mail sent at a specified time?  I am thinking of several applications of this.  In my work I'm often away and unable to send an email on a friend's birthday or whatever and it would be nice if by using the "Send Mail Later" feature I could be taken to a dialog that would, much like a "To Do" event, ask me to choose the time and date that I would like to send the email.  

Another option would be to have all outgoing mail delayed long enough (say, 2 minutes) that I would have time to cancel it or (as I know we all do!) attach the forgotten attachment that we're referencing and so on.  Few things look sillier than "Please see my resume attached below" and having to follow it with a "Dooh!" email 2 seconds later.

In my case, the "Send Mail Later" feature seems to just put it in the Outbox rather than in the draft folder, and to send it I have to Edit it again and then click send the way I normally would.  It never seems to send if I just leave it there.  Nor do I have any access to any configuration options to set this up.  I'm not even sure what the usual functionality is.

I am running Fedora 8 with Kmail version 1.9.10.  It seems like it would be incredibly useful to have a timer countdown and/or a calendar send feature for outgoing email.  I am thinking of upgrading to Fedora 11...might this be working in that?

Thank you!