Issue with inbound filename retrieval

Greetings,

I have a simple BPM that loops,(in a block), through a file, calls a BAPI, and outputs to a file.

I've added a mapping that isn't part of my BPM to try & retrieve the inbound filename from the DynamicConfiguration of the SOAP Header of my receive step.

Could someone please give basic steps or point me to a blog that shows

how to add the mapping external to my BPM, but still part of my process.

Thanks,

Doug -