How to handle the multiple interfaces at the USB DDK

Hi, I’m using QNX 6.3 SP2, and how should i
handle the multiple interfaces in a usb device
driver? ie. interface 0 corresponding to control, interrupt, bulk in/out
while interface 1 corresponding to iso in/out, so when i want to use
interface 1 for communication, what steps i should follow?

Thanks

Regards
Jason