CAN-BUS shield + arduino, different buttons but same message

Hello,

I have the volvo s80 car 2008, i trying to capture steering wheel button 
presses, the problem is when i press the two different buttons i receive 
the same can-bus message, for example:

1. When i press "Exit" button i receive:
canId = 0x7A, message =  0x0 9F 80 0 0 0 0 21 0

2. When i press "Enter" button i receive the same message:
canId = 0x7A, message =  0x0 9F 80 0 0 0 0 21 0

If i press other buttons(for example "cruise control start" on steering 
wheel or some button on radio) i receive uniqueness messages and last 
bytes changes for each other button presses.

I'm using arduino and can-bus shield(elecfreaks), maybe somebody can 
help me and explain what can be wrong, here is my arduino sketch:

#include <SPI.h>
#include "mcp_can.h"

const int SPI_CS_PIN = 10;

MCP_CAN CAN(SPI_CS_PIN);                                    // Set CS 
pin

void setup()
{
    Serial.begin(115200);

START_INIT:

    if(CAN_OK == CAN.begin(CAN_125KBPS))
    {
        Serial.println("CAN BUS Shield init ok!");
    }
    else
    {
        Serial.println("CAN BUS Shield init fail");
        Serial.println("Init CAN BUS Shield again");
        delay(100);
        goto START_INIT;
    }
}


void loop()
{
    unsigned char len = 0;
    unsigned char buf[8];

    if(CAN_MSGAVAIL == CAN.checkReceive())            // check if data 
coming
    {
        CAN.readMsgBuf(&len, buf);    // read data,  len: data length, 
buf: data buf

        unsigned char canId = CAN.getCanId();

        Serial.println("-----------------------------");
        Serial.println("get data from ID: ");
        Serial.println(canId);

        for(int i = 0; i<len; i++)    // print the data
        {
            Serial.print(buf[i]);
            Serial.print("\t");
        }
        Serial.println();
    }
}