Back in October 2010, MS Exchange Team released a small tool that can help you to find the Processor Configuration that must be filled in Exchange 2010 Mailbox Role Calculator.
The tool name is Exchange Processor Query Tool, you can find more information about it from this link and you can download it from this link.
An example on how to use it here.
Happy Exchange 2010 Mailbox Role Calculating!
Update! get the latest version of this handy tool from the this link.