Windows 7 - problem with realtek configuration and surround sound

Hi all,

I use the Realtek HD driver 6.0.1.6000 to manage the sound.
The Realtek control panel just show the 'Digital Output' screen (see attached picture) and I don't have the 'Speakers' screen that would allowed me to configure my sound system as 5 speakers + 1 sub.

Then, I can't convert the stereo stream intput into AC3 5.1 stream for the AV Receiver (through the card's spdif output) when using Internet explorer (film in streaming) or when using Windows Media Center (digital TV).

At least would it be possible to transmit PCM stream that would allow the AV receiver to use its own Dolby Pro Logic engine to have surround sound ?

Comments :
- multi-channels DD and DTS work well.
- stereo conversion to AC3 5.1 stream works well also with KMPlayer + AC3Filter
- but I can't convert stereo stream of film into surround sound

Thanks for any help or comment,

Laurent