Outlook mail passwords.

I recently changed my mail programme from Outlook Express to Outlook. For business reasons my incoming POP has a different password from my outgoing SMTP password. With express the system allowed different passwords - but outlook doesn't seem accept this. When on send/receive I have to enter my POP password - then enter my SMTP password in a drop down window - then change it back again for my next send/receive. Its a real pain - is there a solution ??