Udev rules

I could'nt configure any usb device, because yast do'nt detect it, because not loads any usb module (for example, the usb printer). I have updated the system via apt, and have the kernel from the date 29/12/05, but the yast modules are not completely updated. For configure the sound, I must run alsaconf, and later the yast, and restarting the kde, and then the sound works; but if I restart completelly the system the sound do'nt works, because not loads any sound module, and the sound devices has disappeared. I mean that the problem, is that yast do'nt writes the udev rules. Can You tell me how it works? Thanks, Juan