Problema Arduino mega 2560 + GSM/GPRS&GPS SHIELD V2

Scusate se riapro la discussione.

ho seguito tutte le info e sono riuscito a far funzionare gsm-shield versione 1 su arduino mega

SERIALE HW
pin RX gsm su PIN 19 mega
pin TX gsm su PIN 18 mega

funziona quasi tutto , ho utilizzato questo codice

#include "SIM900.h"
#include <SoftwareSerial.h>
//If not used, is better to exclude the HTTP library,
//for RAM saving.
//If your sketch reboots itself proprably you have finished,
//your memory available.
//#include "inetGSM.h"

//If you want to use the Arduino functions to manage SMS, uncomment the lines below.
#include "sms.h"
SMSGSM sms;

//To change pins for Software Serial, use the two lines in GSM.cpp.

//GSM Shield for Arduino
//www.open-electronics.org
//this code is based on the example of Arduino Labs.

//Simple sketch to send and receive SMS.

int numdata;
boolean started=false;
char smsbuffer[160];
char n[20];

void setup() 
{
  //Serial connection.
  Serial.begin(9600);
  Serial.println("GSM Shield testing.");
  //Start configuration of shield with baudrate.
  //For http uses is raccomanded to use 4800 or slower.
  if (gsm.begin(2400)){
    Serial.println("\nstatus=READY");
    started=true;  
  }
  else Serial.println("\nstatus=IDLE");
  
  if(started){
    //Enable this two lines if you want to send an SMS.
    if (sms.SendSMS("3334445566", "Arduino SMS"))
      Serial.println("\nSMS sent OK");
  }

};

void loop() 
{
  if(started){
    //Read if there are messages on SIM card and print them.
    if(gsm.readSMS(smsbuffer, 160, n, 20))
    {
      Serial.println("letto");
      Serial.println(n);
      Serial.println(smsbuffer);
    }
    delay(1000);
  }
};

parte , mi invia il messaggio e rimane in attesa di ricevere un SMS

io invio un SMS ma lui non me lo stampa a video !!!??

HELP me

Grazie