I found a way to do it. When I add the line:
project.SetVar(_T("MCU"), Processor, false);
to the avr wizard script, I see the "MCU" variable paired with the avr type (processor var in the script) on the "Custom Variables" tab. Is there a more convenient way to do this or shall I deal with this no longer? And is there also a compiler specific menu? Like when the AVR compiler is chosen a user tools menu including only the tools chosen about AVR.
Regards...