Hi Gianluca Ghioni, 

Try to use  for a instance 

the method GetRequestHeader of the 

HTTPRequestHandler API

https://success.outsystems.com/documentation/11/reference/outsystems_apis/httprequesthandler_api/

Hope that it helps you 

Hi Gianluca,

Sorry for just getting back to you now. Don't know if you've managed to solve this meanwhile, but the reason for the problem is where you are calling GetSOAPHeaders_FromRequest.

There are 2 steps when trying to use the Get<something>Headers Actions:

1. Call the RegisterInspectHeaders Action inside the OnBeforeRequestAdvanced
2. In the flows of other Actions, where you want to call some of the service's SOAP Action, you should add right after that a call to the relevant SOAP Extensibility Action.

So in the example above, after calling GetPatients Web Method, we call GetSOAPHeaders_FromReponse.

Let me know if this helps!

Cheers