Alarm notifications for Siemens PLCs - by: emitter

Hello!

I'm very newbie in OPC UA, and currently could not find out how to use the sample client AcknowledgeMain1.cs for Siemens PLCs (SIMOTION, resp. S7-1500).
In UAExpert I can add the desired alarm&event node and observe the alarms. But the sample client does not catch them (timeout after 30 seconds).

In case of SIMOTION the node attributes are:
"ns=2;s=opcua/events.useralarms."

In case of S7-1500:
"ns=3;i=1814"

In the code I tried almost every possible combinations, but neither did work for me:

//SIMOTION:
new UANodeId(expandedText: "nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=opcua/events.useralarms.")
new UANodeId(expandedText: "nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=opcua/events.useralarms.1")
new UANodeId(expandedText: "ns=2;s=opcua/events.useralarms.")
new UANodeId(namespaceIndex: 2, identifier: "opcua/events.useralarms.")
new UANodeId(namespaceIndex: 2, identifier: "opcua/events.useralarms.1")

//SIMATIC S7-1500:
new UANodeId(expandedText: "nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=3;i=1814")
new UANodeId(expandedText: "ns=3;i=1814")
new UANodeId(namespaceIndex: 3, identifier: 1814)

(see also screenshot)

What am I doing wrong?
Thanks!