M-Audio Fast Track Ultra 8R can't get S/PDIF out to work

[colonel_claypoo]

hello,

i am a new user of the fast track ultra 8r.
i want to connect my denon pma-500v stereo amplifier via s/pdif to the interface.
the denon should receive the signal from the s/pdif output and play it back through speakers.
it should not be the input device for the interface.

the problem is that i just can't get this scenario to work. i've tried everything i could think of.
i tried using a s/pdif to 6,4mm adapter and i plugged it into the either output 7 or 8 from the interface.
this way the denon receives a signal from the interface but it mono, of course.

so that tells me that the s/pdif out somehow does not work as it supposed to right?
i have the set the sync source of the interface to internal. if i set it to external it would mean that the s/dif out of the interface becomes an input right? so that's also not correct.

the RCA cable shouldn't be broken. i have used it with my edirol ua-25 by plugging it into it's s/pdif outputs and it worked fine.

RCA and s/pdif is the same right? i hope that's not the problem.
if there were a difference between RCA and s/pdif and the denon amplifier only had RCA ins and outs then that could be the reason why the s/pdif of the interface doesn't work.

does anybody have a clue?

i'm on winXP SP3 by the way.

thanks!