changing the pinmap file in SD library

Hi,
My Arduino board uses this microcontroller http://www.atmel.com/Images/doc2503.pdf and i need to change the pinmap file so that it detects my microcontroller and i can use SD library. I changed pin numbers suitable to my controller ( SS_PIN , MOSI_PIN , MISO_PIN and SCK_PIN ) and also tried changing the name in the following code by AVR_ATmega32 instead of AVR_ATmega1280 or AVR_ATmega2560 but it din't detect. can anyone please tell me how should i name it so that my controller is detected.

#if defined(AVR_ATmega1280) || defined(AVR_ATmega2560)
// Mega

// Two Wire (aka I2C) ports
uint8_t const SDA_PIN = 20;
uint8_t const SCL_PIN = 21;

// SPI port
uint8_t const SS_PIN = 53;
uint8_t const MOSI_PIN = 51;
uint8_t const MISO_PIN = 50;
uint8_t const SCK_PIN = 52;

plz guide me , thanks.

So that's basically a low memory version of a '644/'1284 chip.
I would install maniac bugs '1284 files and work from there to see the formats & stuff needed for IDE 1.0 if that's the version you are using.

I suggest you use Arduino 1.0 and SdFatBeta20120327.zip at Google Code Archive - Long-term storage for Google Code Project Hosting..

This version of SdFat uses the definitions for SS, MISO, MSIO, and SCK in the hardware/arduino/variants//pins_arduino.h file.

The pin map file is going away since SPI pins are now defined in the above file.

Thanks CrossRoads and fat16lib for your suggestions, i will work on it.