Arduino Mega2560 as ISP to program another Arduino Mega2560

Hi there,
yes! A Bug's it!
I can use an Arduino Mega 2560 a 328P flashen- without problems.
I can not flash with an Arduino Mega 2560 a Mega 2560.
This only works with foreign hardware or complicated changing the software.
But no one understands. What is this?
Greeting and fun
Andreas

P.S. I try to just:
Arduino Maga 2560 -> Mega 2560
http://www.ebay.de/itm/Mikrocontroller-Atmel-ATMega2560-ATMega-SMD-Adapter-/271224130246?pt=Bauteile&hash=item3f2637cac6