All I actually had to do
was to add the following two lines to /etc/modprobe.d/alsa-base:
--------------
options snd-intel8x0 index=0
options snd-usb-audio index=-2,-2
--------------
It took me two months and four different forums/mailing lists to find out... I
still think that it is the job of the desktop environment to search the
configured soundcard at startup instead of letting poor users change system
configuration files as root to hardcode the soundcard order. What do you
think of the proposals I made here:
http://lists.kde.org/?l=kde-linux&m=116803699028792&w=2
Is there any developer here who can give some feedback? Are those proposals
realistic? (I would help designing, testing and documenting this feature with
the help of a KDE developer.)