code: public void processThisMessage()
      {
          Utility.getLogger().info("On message called in receiving process");
          try {
              BaseMessage messageIn = this.getMessage();
              if (messageIn != null)
              {
                  BaseMessage messageReply = this.createReplyMessage(messageIn);
                  this.moveScreenParamsToMessage(messageReply);
                  // Step 2 - Get the body part of the message
                  this.getTransport().setupReplyMessage(messageReply, messageIn, MessageInfoTypeModel.REPLY, MessageTypeModel.MESSAGE_IN);
              
                  this.getTransport().processIncomingMessage(messageReply, null);
              }
          } catch(Exception ex) {
              ex.printStackTrace();
              Debug.print(ex, "Error in processing or replying to a message");
          }
      }
docs: This is the application code for handling the message. Once the
  message is received the application can retrieve the soap part, the
  attachment part if there are any, or any other information from the
  message.