If you want to add additional e-mail address to your public folder in Exchange 2007 Service Pack 1 (BETA!!!!) you open Exchange Management Console, select Toolbox and open Public Folders Management Console. On Public Folders - SERVERNAME right-click and choose Connect to Server... --> Browse and Select the server from the list. Under Default Public Folders choose the public folder you want to add additional e-mail address to and in the right-click menu choose Properties --> E-mail Addresses.
To add additional e-mail addresses to Public Folder in Exchange Management Shell (pre-SP1 and SP1) use following commands:
First, always check what is already in...
Get-MailPublicFolder -Identity "YOURPUBLICFOLDERNAME" | FL
You need to disable Email Address Policy for this Public Folder (like uncheck - Automatically update e-mail addresses based on e-mail address policy)
Set-MailPublicFolder -Identity "YOURPUBLICFOLDERNAME" -EmailAddressPolicyEnabled:$FALSE
Then add additional e-mail addresses...
DON'T FORGET - you need to enter ALL e-mail addresses this Public Folder will use INCLUDING all e-mail addresses that are already in.
Set-MailPublicFolder -Identity "YOURPUBLICFOLDERNAME" -EmailAddresses email@example.com,PRIMARY@domena.si,firstname.lastname@example.org
Set-MailPublicFolder -Identity "YOURPUBLICFOLDERNAME" -PrimarySmtpAddress PRIMARY@domena.si