Identities!

1. Click on File, Identities, Manager Identities, New, Enter the persons Name (or e-mail address, just so you can Identify what the account is) and click on OK
2. After doing so, say YES you would like to switch the accounts, and then it will use the internet connection wizard to set up the new account. 
3. First it asks for the Name you want to be displayed on each outgoing e-mail. It will then ask you what the e-mail address is (should be on the I already have an e-mail address that I'd like to use) Enter the e-mail addresses, and click Next
4. Enter the POP3 Incoming server, and then the SMTP outgoing server and press Next
5. Should already have your Username, enter the password and check [x] Remember Password, Click on Next. That should be it! It might ask you what connection you want to use, you can select the Dial-Up Networking Connection, or you can just put it on LAN.
6. Finish!