Another M-audio Fast Track Question, having problems with cubase sx Options

[soul crates]

helloo folks.

this might be a ridiculous or even stupid question for some of you, but please help me...

i received this fast track interface today and it works fine with iTunes and quicktime, but i can't make it work in cubase / can't switch between built in to fast track on the master channel. what am i doing wrong? do i need to install any asio driver or something?

any help highly appreciated...