OK so I am using a hacky solution to this - basically I use a simple powershell script to change the FROM just before my mails go out.

I run this...

If you want to change it permanently, you can do the following:

In the rsreportserver.config file (sql drive:\Program Files\Microsoft SQL Server\MSSQL.3\Reporting Services\ReportServer):

5) Populate <SMTPServer>x.x.x.x</SMTPServer> with the IP of the machine where...

Yes it isn't suggested in the context of the task, but you can put *.* in the sourcefile to ftp ALL files down regardless of name.