Windows Media Encoder with multichannel AC3 audio

I have some video content from a DVD with the following properties:Video: MPEG2 Video 720x480 (4:3) 29.97fps 9800Kbps [Video]
Audio: Dolby AC3 48000Hz 6ch 384Kbps [Audio]

I am using Windows Media Encoder to convert this to WMV, but I cannot for the life of me get multichannel audio to work. If I try just stereo, everything works fine:Audio encoding mode: Bit rate VBR
Video encoding mode: Bit rate VBR
Audience: 5393 Kbps
Audio codec: Windows Media Audio 10 Professional
Audio format: 384 kbps, 48 kHz, 2 channel 24 bit VBR
Video codec: Windows Media Video 9
Video bit rate: 5000 Kbps
Video size: Same as video input
Frame rate: 29.97 fps
Key frame: 2 s

If I try to get all 5.1 channels, though, I get an error:Audio encoding mode: Bit rate VBR
Video encoding mode: Bit rate VBR
Audience: 5393 Kbps
Audio codec: Windows Media Audio 10 Professional
Audio format: 384 kbps, 48 kHz, 5.1 channel 24 bit VBR
Video codec: Windows Media Video 9
Video bit rate: 5000 Kbps
Video size: Same as video input
Frame rate: 29.97 fps
Key frame: 2 s

The error I get is upon pressing the Apply button (which would normally apply all settings and give you a preview of the results):The following error occurred while setting up the source ‘Convert’:
The input media format is invalid.(0xC00D0BB8)
[OK] [Help]
I’m at a loss as to what to do. Any audio settings I try with 2 channels work, any audio settings with 5.1 do not work. Any help appreciated.

I have been having the same problem. It is only when I have windows media audio 10 in windows media encoder and attempt to encode anything in 5.1