I want to add some data to my event on a opcua server using open62541

What worked so far:
I added a new Event to BaseEventType.
I can send severity and time from my server to OpcUaExpert

My Issue :
I want to add a property for example “TemperatureEvent” to my event type “CustomEvent”.
OpcUaExpert shows this property in the address space Root – Types – EventTypes but I cannot see the value of the temperature in the eventView.

Pictures OpcUA Expert:
enter image description here

MyServerCode:

addObjectTypeNode and addVariableNode to my Event “CustomEvent”

    UA_ObjectTypeAttributes attr = UA_ObjectTypeAttributes_default;
    attr.displayName = UA_LOCALIZEDTEXT("en-US", "CustomEvent");
    attr.description = UA_LOCALIZEDTEXT("en-US", "Event for ...");
    UA_Server_addObjectTypeNode(server, UA_NODEID_NULL, UA_NODEID_NUMERIC(0, UA_NS0ID_BASEEVENTTYPE),
                                UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE),
                                UA_QUALIFIEDNAME(NamespaceIndex, "CustomEvent"), attr, NULL, &eventType);

    // Add Temperature field to the event type
    UA_VariableAttributes temperatureAttr = UA_VariableAttributes_default;
    temperatureAttr.displayName = UA_LOCALIZEDTEXT("en-US", "TemperatureEvent");
    temperatureAttr.dataType = UA_TYPES[UA_TYPES_DOUBLE].typeId;
    UA_NodeId temperatureAttrId;
    UA_Server_addVariableNode(server, UA_NODEID_NULL, eventType, UA_NODEID_NUMERIC(0, UA_NS0ID_HASPROPERTY),
                              UA_QUALIFIEDNAME(NamespaceIndex, "TemperatureEvent"),
                              UA_NODEID_NUMERIC(0, UA_NS0ID_PROPERTYTYPE), temperatureAttr, NULL, NULL);


    std::thread threadObjTriggerEvent(threadTriggerEvent, server);

Trigger the event in a thread (executed every x seconds)

        UA_NodeId eventNodeId;
        UA_StatusCode retval = UA_Server_createEvent(server, eventType, &eventNodeId);

        // informations for ua expert
        UA_DateTime eventTime = UA_DateTime_now();
        UA_Server_writeObjectProperty_scalar(server, eventNodeId, UA_QUALIFIEDNAME(0, "Time"), &eventTime,
                                             &UA_TYPES[UA_TYPES_DATETIME]);

        UA_UInt16 eventSeverity = 100;
        UA_Server_writeObjectProperty_scalar(server, eventNodeId, UA_QUALIFIEDNAME(0, "Severity"), &eventSeverity,
                                             &UA_TYPES[UA_TYPES_UINT16]);

        UA_LocalizedText eventMessage = UA_LOCALIZEDTEXT("en-US", "An event has been generated.");
        UA_Server_writeObjectProperty_scalar(server, eventNodeId, UA_QUALIFIEDNAME(0, "Message"), &eventMessage,
                                             &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);

        // Event data: Temperature
        UA_Double temperature = 23.5;// Example temperature value
        UA_Server_writeObjectProperty_scalar(server, eventNodeId, UA_QUALIFIEDNAME(2, "TemperatureEvent"), &temperature,
                                             &UA_TYPES[UA_TYPES_DOUBLE]);

        // trigger this event
        retval = UA_Server_triggerEvent(server, eventNodeId, UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER), NULL, UA_TRUE);      

Maybe someone knows what I am doing wrong, thanks !