SPDIF output only stereo Content Realtek

My SpDIF (Realtek Digital Output) only outputs stereo content even when playing DVD's. My receiver shows receiving 5,1 and 6.1 but only the stereo speakers and the subwoofer have sound. When I test "supported formats" dts and dolby only the SW and front speakers play sounds but the receiver shows 5.1 input. I know the speakers work because I hooked them up to analog and the receiver test went fine.

I Have MSI X58 Platinum MB with Realtek on-board and latest driver 2.14 from realtek site. In properties I only have an option for 2 channel output. Shouldn't there be options for 6 channel and 8 channel output? Using Vista Ultimate X64 for gaming and home theater and stereo just doesn't cut it. No problems in XP with older system.

How can I get multichannel SPDIF? thanks for listening.

Update - Forgot to reset my receiver when I switched back to digital from analog. I reset it to enhanced surround. Now the 5,1 and 6,1 are coming from the appropriate speakers for DVD's. My TV tuner was compatible with windows media center so now am getting 5.1 sound from digital TV. Now if I could just get digital spdif 5.1 sound for left 4 dead, bioshock, painkiller, far cry 2 I could give Vista a thumbs up.