For those of you who are interested in setting up Exchange Server to work with a Powweb mailbox, I finally got it to work. I thought it would be nice to pass this info on to you guys.

I'm using SBS 2008 with Exchange 2007.

For receiving e-mail:
1- Create the mailbox on Powweb.
2- Create a user and e-mail in SBS 2008 Console (if you don't have SBS server then you do this in Active Directory).
3- Create a POP3 Connector in SBS 2008 Console (if you don't have SBS server then you do this directly in Exchange).
4- Under "Manager POP3 Mailboxes", add a mailbox and use the following settings:
POP3 server: pop.your-domain-name.com
Port: 110
User Name: (mailbox name created in powweb i.e. johndoe@yourdomain.com)
Password: (password created in powweb)
Select the e-mail account (from the drop-down) to associate with the POP3 account.

Note: Repeat procedure above to add more mailboxes.

For sending e-mail:
1- Open Exchange Management Console (EMC)
2- In the left pane expand Organization Configuration, Hub Transport and select "New Send Connector" and follow the wizard:
Name: I recommed using the mailbox name here i.e. johndoe
Select the intended use of this Send connector: Select Internet
Address Space: Select "Add" and only put in an asterik
Network settings: Select "Route mail through the following smart hosts"
Select "Add" and select "Fully qualified domain name" FQDN and enter smtp.your-domain-name.com
Configure smart host authentication settings: Select "Basic Authentication" and enter the user name and password (this is the mailbox created on Powweb i.e. johndoe@yourdomain.com)
Select "New" to create the send connector
3- Open "Exchange Management Shell" (looks like a command prompt window) and enter the following command:
Get-SendConnector -Identity "use-the-Send-Connector-name-here-within-the-quotes" | fl (this will display a lot of info, but we are interested in the Port number which by default should be 25. Next, we need to change the port number to 587 by using this command:
Set-SendConnector -Identity "use-the-Send-Connector-name-here-within-the-quotes" -port 587

Note: Repeat procedure above to add more mailboxes.