Xmega arduino Board Xaduino - Problems with code definition

Hello guys, a buddy gifted me a Xaduino (128A3U board, http://www.obdiiworld.com/) and i used the altered version of the arduino IDE provided in the link. Since the Xarduino board is defined as 128A3 and not 128A3U lots of Register definitions (in iox128a3.h) are missing and i added the missing file from Atmel Studio and changed the mcu type in the boards.txt. Now i´m getting following error :

unknown MCU 'atxmega128a3u' specified
Known MCU names: ...

Is this due to an old avr dude version or can i add mcu´s anywhere ?