Last December I blogged about a bug in the MailServer object, in that they left out a New() method for creating a MailServer object. The full description of the error and workaround is here and the Connect item I filed on the problem is here..
In browsing through the SMO Object Library for SQL Server 2008 I see they still have not included a New() method for the MailServer object, so the workaround is still in play.
Allen