So I have been going around in circles for the last 20 minutes trying to edit the default email address policy in exchange 2010 and when I use the EMC to do that it fails with some "Conditional Attributes" message!! such a pain.. so anyhow I think I might have found out how to edit the dam policy but its through the EMS not EMC and the command I run is

get-emailaddresspolicy default* | set-emailaddresspolicy -enabledemailaddresstemplates SMTP:%g.%s@alstar.com,smtp:%g.%s@alstarfilms.com

Note: =

Update-emailaddresspolicy -Identity default*

Hope this helps and let me know if you manage to find alternate ways to achieve this shit!

-Alstar