Enabling digital out with Alsa 1.0.1 and higher (VERY IMPORTANT)

wiki:alsa [Notes]: "Enable digital output with Alsa 1.0.1
Something have change in Alsa, from version 1.0.1. It seems that now, when enabling the digital output, the analog on is shut down. Anyway, you need to enable the loopback to convert Analog to Digital, doing:

options snd-ac97-codec enable_loopback=1

Then, turn on, in alsamixer, the ADC/DAC.
Some other thinks have to be done, it's strange:

***Mute the IEC958 Optical Raw***"