From Books online:
[ @username = ] 'username'
The username to use to log on to the e-mail server. username is nvarchar(128), with a default of NULL.
[ @password = ] 'password'
The password to use to log on to the e-mail server. password is nvarchar(128), with a default of NULL.
So you should know the username you want to be used in the profile and the password. If you don't know ask your mailserver administrator. In case your mailserver does not require authentification you can leave both values NULL, but most mailservers require authentification.
[font="Verdana"]Markus Bohse[/font]