Sending calculated header values (Plain HTTP Adapter)

Hi,

I'm new at HTTP communication in PI and I have the following scenario in SAP PI 7.1:

HTTP - PI - HTTP

PI receives a message from an external server and delivers to an external client.

The communication is synchronous and both adapter types are HTTP, the sender and receiver channel have the following configuration:

   fig. 1 - sender configuration

   fig 2 - receiver configuration

When the client receives the sent message, he processes it and sends the response as an calculated header field, as shown in the following image:

   fig. 3 - synchronous response received when server consumes directly the client server via "Poster" Mozilla Add-on)

But if I send the message via PI, I don't receive this header in the response:

   fig. 4 - synchronous response received when server sends the message through PI via "Poster" Mozilla Add-on)

How can I obtain the header field "X-XPTO-STATUS" that is sent by client and send it to the server as a header field also?

If you can point me the direction I'll be grateful.

Thank you in advance.

Sandra