Question : multiple physical sites with SBS 2008

Hi there,
so here's the proposed scenario. I am currently running SBS 2008 premium in my main office on 2 physical servers (one is dc + exchange, the other is SQL server). Both servers are behind a juniper firewall.
My company is planning to open a branch office soon, with 3 users that are going to be present over there. Connection to the main office is going to be done to the main office between the juniper firewalls by vpn tunnel (we are installing another one at the remote branch).
due to the very limited bandwidth that is available in my country, (max speed is 2 mbps assymetrical) I am looking at deploying another sbs 2008 server at the remote site. I am only interested in two functions, one being a Read Only DC, and the second being an exhange server. However, I would like to have all e-mails on the same domain, i.e. at the mails would all look like [email protected], no matter where the users are. I need a local exchange server because I have a lot of e-mail trafic, with pretty heavy attachments.
Any ideas how to do it  ?

Answer : multiple physical sites with SBS 2008

So, here is the thing if you are have 2 Exchange servers the primary Exchange will have to route the traffic to the other Exchange in the remote site so you would still be using your low bandwidth no matter what. The mail still must travel through your slow connection between sites.