VC-1 Smooth Streaming with 5.1/6 channels?

Hello,

I am trying to create a job preset in IIS to use VC-1 Smooth Streaming with 5.1/6 audio channels but not sure how to accomplish this. I have set the "channels" attribute value to 5.1 and 6 but both fail.

<WmaAudioProfile
            Codec="WmaProfessional"
            Channels="6"
            BitsPerSample="16"
            SamplesPerSecond="44100"><Bitrate><ConstantBitrate
                Bitrate="320"
                IsTwoPass="False"
                BufferWindow="00:00:00" /></Bitrate></WmaAudioProfile>

5.1 fails because it is expecting an integer but 6 channels also fails saying: 

Error The Audio Profile settings do not match a valid system profile.

Could someone please explain the proper way to encode to VC-1 Audio with 5.1 channels?