damn that was some kind of a nightmare time consuming.
here is the process i've followed :
the DS-1 dirver is not good => manage to change it to DS-XG WDM :
1- go & download the ds-xg driver on the net (there's a set up in it), maybe u can go and look for "dsxgxp" this is the name of one of the ones i've used
2- perform the install
3- after rebooting, in my case, so i guess also in yours, Win XP still goes for his driver of DS-1 instead of the DS-XG you've just installed. Then :
4- go through your peripherical gestionnary (i don't know how you say that in english, this is right click then properties of the icon "work post")
5- in the list of the material you've on your computer go to audio controllers, here will be the DS-1 drivers
6- on each one of these driver, click properties & then go to update the pilot
7- say that you wanna go to a specific place not the automatic install
8- then whether it will automatically propose you the DS-XG driver wether you'll have to go through the list of all the manufacturer and find it
9- once you have changed all these DS-1 drivers (2 for audio, 1 for game controller in my case), reboot
10- once you've rebooted, go to configuration panel, & then you'll see an icon called "config. YAMAHA DS-XG" .
11- open it, go to the output line and select "special 4 channel"
12- and here you'll now are supposed to have your 4.1 on
Update me if it's working for you as it did for me. I'm back to life with all this sound now!!!!!
'd luck guys