Fetching Ens.MessageHeader properties starting from an EnsLib.HL7.Message in an Ens.BusinessProcess class

I have a handful of EnsLib.HL7.MessageRouter sending an HL7 message to a single Business Process (Ens.BusinessProcess).

In the OnRequest method, I am declaring pRequest as EnsLib.HL7.Message

What I need to do is determine which HL7 Router sent any given request to my BusinessProcess. 

To do this, I know that I need to fetch the SourceConfigName property from the Ens.MessageHeader of the Request, but I am not sure how (or if) I can fetch this data from within the OnRequest Method.

Does anyone have any pointers?

Bill Casey