Get SOAP header information

Dear,

In our synchronous scenario SOAP <-> SAP PI <-> ABAP proxy, I face a problem reading the SOAP header from the incoming message.

PI version used is 7.11

This is how the incoming SOAP header looks like

What I need is the content of field UserId.

Already tried a lot and also ticked this option in the sender SOAP adapter: Do Not User SOAP Envelope.

If I do that, I get an error saying premature end of file.

Any lead is welcome.

Thanks a lot!

Dimitri