Qrexec-client-vm with parameter is denied

I’m working along the documentation of: “Disposable sys-net: Automatically connect wifi (config file or RPC service)”

I worked through all steps including 2.2 and all of them did what they should do.

As I want to hold all my password related stuff in my vault vm,
I’ll try to change point 2.3 to work with my vault vm instead of @adminvm in dom0.

This is the 30-user-policy as created in the documentation:

qubes.user.ConnectWifi +home sys-net-dvm @adminvm allow
qubes.user.ConnectWifi +work sys-net-dvm @adminvm allow
qubes.user.ConnectWifi * @anyvm @anyvm deny

(home and work are the wifi ssids, sys-net-dvm is the disposble network vm)

and the belonging call from sys-net-dvm is

qrexec-client-vm @adminvm qubes.user.ConnectWifi+$rpc_arg /rw/config/qConnectWifi

($rpc_arg is ‘home’ or ‘work’)

I’ve changed those two parts to the following:

30-user.policy:
qubes.user.ConnectWifi +home sys-net-dvm vault allow
qubes.user.ConnectWifi +work sys-net-dvm vault allow
qubes.user.ConnectWifi * @anyvm @anyvm deny

the call:
qrexec-client-vm vault qubes.user.ConnectWifi +$rpc_arg /rw/config/qConnectWifi

The script /rw/config/qConnectWifi exists in sys-net-dvm.
The script qubes.user.ConnectWifi exists in vault in the correct directory /rw/usrlocal/etc/qubes-rpc.

On the commandline I get “Request refused” and as notification box a bit more: “Denied: qubes.user.ConnectWifi from sys-net-dvm to vault”

As I did all my tries only by editing the existing files from the first parts of the doc, I’m pretty sure all needed files are in the right place, so in my eyes it must be the syntax of policy file and/or the call what don’t fit.

What is wrong here?