AVR32 nested interrupts?

Unfortunately I early on had the impression I could have some FreeRTOS aware interrupts and some that were outside its scope (think motor control) for AVR32 – but I was wrong. So, the question is – what would I have to do to make this work? Can anyone give me some pointers on what code I need to modify to make this work? I have a real motor I need to control at int3 level, in assembler, and cannot afford to block that level. Any pointers appreciated! David