[systeminfo] how to show ip-address of second interface

I have two interfaces on my OH server. I want to monitor the traffic of these interfaces. But I do not get the second one to work:

My config:

String Network_IP1 "Netzwork-IP[%s]" { channel="systeminfo:computer:work:network1#ip" }
String Network_IP2 "Netzwork-IP[%s]" { channel="systeminfo:computer:work:network2#ip" }

According to the documentation this should give me the values of both ip-addresses. But I get no values.

If I use

String Network_IP1 "Netzwork-IP[%s]" { channel="systeminfo:computer:work:network#ip" }

I will get the ip-address from interface 0. Which means the systeminfo binding is working but I made a mistake with interpreting the syntax for the second interface?

I not totally understand what this part of the documentation will tell me:

The groups marked with "(deviceIndex)" may have device index attached to the Channel Group.
channel ::= channel_group & (deviceIndex) & # channel_id

Any hint?