🚀 go-pugleaf

I have a Denon DD5.1 receiver through which I run a DVD player using the
coaxial input so I know all speakers work properly. I connected my SBLive
5.1
sound card to this coaxial input on the Denon using a mini-phono wire from
the digital output of the sound card. This mini-phono wire goes through a
splitter to RCA left and right connectors, one of which is plugged into the
receiver's coaxial input. While I don't have a wiring diagram, I tried both
the left and right splits of the RCA cable and both work the same. I believe
there is only one digital signal output and by using a stereo mini-phono
wire
I'm simply getting the same signal on the left and right RCA connectors.

When I select "digital output only" and "5.1" for the speaker configuration
in the Creative Mixer the receiver plays the sound from its coaxial input.
However, when I select the "test" option I don't hear anything in the rear
channels when they are highlighted... I only hear the front 3 speakers. The
Denon receiver says "Dolby Prologic Surround" all the time. When I watch a
5.1 DVD I'm used to seeing "Dolby Digital" displayed instead.

I still get sound in the rear speakers when I play games where I can select
"surround mode" (such as Unreal Tournament) so the speakers are working, and
when I use Winamp I can hear some sounds in the rear speakers depending on
the music, but I think these rear speaker sounds are a side effect of the
receiver's surround processing. Most CDs and MP3s are not encoded in Dolby
Prologic Surround, right?

Is the problem that I've hooked something up wrong or haven't set an option
somewhere in Win98SE? Or is the problem simply that there is no built-in
support to translate the normal stereo computer output into a Dolby Prologic
Surround or Dolby Digital signal which uses the rear speakers?

If it is the latter, can someone recommend an MP3 player or some good DD5.1
games which can take advantage of the 5.1 rear channels through the SBLive
5.1? So far, hooking up my sound card to my DD5.1 receiver using the digital
output has had no advantage over what I already had on a normal Left-Right
pair of analog RCA cables.