I haven't got a clue how the A330 is wired but i recon you have two main AC buses.. (sit corrected)
(Boeing)
The APU generator will not connect to anything (bad/smoking bus or the good one) until your good generator decides to go a-wall and kick out.. Then I'm sure the APU gen would kick in and deliver the goods..
This is if you haven't been fooling around with the BUS TIE switches..
regards..