From previous advice I've created my Domain Controller (2008R2) with a mydomain.local name (instead of mydomain.com, split DNS scenario) So my users have logins like firstname.lastname@example.org. And for logging in to the servers that fine I guess.
Now on the Same domain I've installed a Exchange 2010 server. (with client access External domain pointing to our public mydomain.com) After install I see that my domain admin is imported and has its own mailbox. When I look at the details I see for email: email@example.com.
Of course this makes sense but its not what I'm looking for. The mailserver should be serving the public .com domain and it would be nice if users can enter with their .com adres and credentials.
So the question is can I configure this and where should I do this to make it work for all new users I import from AD.
For the record I'm still in a test environment. In their I've created forward lookup zone for mydomain.com so I'm able to test all public domain stuff offline before I migrate.