Hello,

This might be useful - and most probably needs improving or at least translation :

the bash-script for linux :
http://ubuntuone.com/2XEmmcNdgBOsTncXiGDLyv

the page where I explain how it works and what are my sources :
http://home-made-dcp.over-blog.fr/article-de-la-stereo-vers-du-pseudo-5-1-vite-fait-via-un-script-122572029.html

Well it's in french...

Best regards,
Gérald