Windows: named pipe in docker service issue

I’ve installed a windows server 2016 build 1709 with docker preview version (docker 17.10.0-ee-preview-3), my goal is to allow a container to communicate with the docker server.

Looking this page https://blog.docker.com/2017/09/docker-windows-server-1709/ I would like to test the “named-pipe mounting feature”.

If i launch this command on my machine:

docker run -d --name testcontainer -v .\pipe\docker_engine:.\pipe\docker_engine microsoft/aspnet:3.5

it works as expected.

My next step is to use the named-pipe mounting on a swarm service, if i launch this command

docker service create --name testservice --replicas 1 --mount src=.\pipe\docker_engine,dst=.\pipe\docker_engine microsoft/aspnet:3.5

I obtain an error saying that the mount target is invalid

1/1: invalid mount target, must be an absolute path: .\pipe\docker_engine.

How should I mount the named pipe on my swarm service?

Thanks in advance
vibstudio