Exchange 2013 Deployment Question

We are upgrading from Exchange 2007 to 2013.  On the new DDeployment, we want to have Outlook Clients connect to an Internal Client Access server but have mobile devices and OWA clients connect through an External Client Access Server.  The reason for this is that we would like to keep the internal outlook traffic from unnecessarily going through our firewall.  Below is the configuration that we are planning:

Server 1:
Client Access and Mailbox Roles - Physical Server
This server will process traffic from Outlook Clients internally.  

Server 2:
Client Access Role - Virtual Server
We want this server to process traffic from OWA and Mobile Devices.  

Is this possible?  If so, what will we need to do to make this work.