Read mail disappears after sending

[Guest plb655]

I've upped my MPx200 to SP2003 (flower), and something very curious occurs when sending mail to my SMTP account: Any mail in the inbox that was previously downloaded from the POP server for that account disppears. Anyone else seen this? A possible workaround would be to create a folder called "keep", if I were able to create new folders! There's nothing in the menu system to do it; is there a way to do this manually?