Temp, Humidity CO2 sensor and library.

Hi DirtGambit ,
I have some difficulties to work with Cozir unit, to change mode and try in Mode2.
I try to send this lines : mySerial.print("K 2\r\n");
and then verify cozir received the message, expecting Response: "K #\r\n" like explain in " cozir software user's guide"
to test the response, I proceed like following:

//essai pour verifie rchangement de mode
while(buffer[ind-1] != 0x0A)
{
if(mySerial.available())
{
buffer[ind] = mySerial.read();
ind++;
}

for(int i=0; i < ind+1; i++)
{
Serial.write(buffer*);//test*
Serial.print("\t");
}
but the response is
? ? ?
So, should it be possible to have your library to understand how it works?
Best regards