Right now, I'm using KDE-4.6, phonon 4.4.4 with the VLC backend. But up to a month ago, I was using KDE-4.4, phonon 4.4.3 with the xine backend, and it was also working. Yes, I've been there, with CLI apps getting the device correctly, and kde not. At the beginning I worked around it by making the device I wanted phonon to use the pcm.!default
Dumb question : you do log out an back in after every change to .asoundrc? I know that made me loose some hair.
Edit : attaching my working asound.rc and my system asound.conf