CL_HTTP_CLIENT Header Uppercase Error REST

Hi ,

I'm trying to consume a API REST from SAP . The web service request as header "efacturaAuthorizationToken" , with the capital letters between word.

I set the header as follows

lo_http_client->request->if_http_entity~set_header_fields(
                          VALUE #(
                             ( name  = 'efacturaAuthorizationToken'
                               value = 'XXXXXXXXXXXXXXXXXXXXXXXXXX' )
                             ( name  = 'Content-Type'
                               value = 'text/plain'  ) ) ).

SAP get this value in lower letter

When I consume the service, the API's response return that this header's value was not send. The API get this value all in low letter. Is there some way where I can send the values with some letters in capital ?

Thank