Is it possible to set it up so that all of my sent messages in Outlook 2007 are automatically sent to a gmail account?

Basically I want to do this for archiving purposes. I have created a rule in outlook that forwards all of my incoming email to the archive email account, but I don’t know how to do this for my sent messages. The email address which I’m using to archive is NOTHING more than an archive email address. I do NOT sync this account with outlook or anything else….