asound devices in .asoundrc

The following works with sb live after muting iec958 optical raw:

from .asoundrc:

iec958 {
type plug
slave.pcm 'hw:0,0'
}
emu10k1 {
type hw
card 0
}

digital {
type plug
slave.pcm digital-hw
}
digital-hw {
type hw
card 0
device 0
}

All of these work:
aplay -D digital bustin.wav
aplay -D emu10k1 bustin.wav
aplay -D iec958 bustin.wav