shairport custom docker - need little help

I'm currently trying to configure a custom docker for shairport (https://github.com/kevineye/docker-shairport-sync) using a pipe, which will then be played by forked-daap.

mkfifo /some/pipe
docker run -d \
    --name shairport-pipe \
    --net host \
    --device /dev/snd \
    -e AIRPLAY_NAME=Docker \
    -v /some/pipe:/output \
    kevineye/shairport-sync \
        -o pipe \
        -- /output

I created the pipe myself using terminal/ssh.

And of course there is no problem with the variables -e and -v. But I don't get how to integrate the last two lines.