RSA5 question?

Hi all,

--Can someone please tell me why I not need to setup in RSA5 when I load CO-PA data from R/3 to BW? Is it because I don't use extractors to load data like Logistic data?

--When do I need to setup RSA5 to load data? When don't I need to setup RSA5 to load data? Please give examples. Any help will be appreciate. Thank you.