NodeJS - @azure/service-bus : How to pass `userProperties` in message to C# backend

Before, I was using azure-sb package to handle service bus message in NodeJS with below sample code:

let message = {
    body: JSON.stringify(body),
    customProperties: {
        userId: userId
    }
};

However, after changed to use package @azure/service-bus, I needed to change a little bit to get body in C# code as below:

let signMessage = {
    body: body,
    customProperties: { // tried to use userProperties but not okay
        userId: userId
    }
};

However, I still cannot get userProperties successfully in C# or ServiceBus Explorer.

Simple code:

const { ServiceBusClient } = require("@azure/service-bus");

const connectionString = "Endpoint=sb://bowman1012.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=xxxxxx"
const topicName = "test";

const messages = [
    { body: "Albert Einstein",
      applicationProperties: {
        userId: 'userId'
      }
    }
 ];

 async function main() {
    // create a Service Bus client using the connection string to the Service Bus namespace
    const sbClient = new ServiceBusClient(connectionString);

    // createSender() can also be used to create a sender for a queue.
    const sender = sbClient.createSender(topicName);

    try {
        // Tries to send all messages in a single batch.
        // Will fail if the messages cannot fit in a batch.
        // await sender.sendMessages(messages);

        // create a batch object
        let batch = await sender.createMessageBatch(); 
        for (let i = 0; i < messages.length; i++) {
            // for each message in the arry         

            // try to add the message to the batch
            if (!batch.tryAddMessage(messages[i])) {            
                // if it fails to add the message to the current batch
                // send the current batch as it is full
                await sender.sendMessages(batch);

                // then, create a new batch 
                batch = await sender.createBatch();

                // now, add the message failed to be added to the previous batch to this batch
                if (!batch.tryAddMessage(messages[i])) {
                    // if it still can't be added to the batch, the message is probably too big to fit in a batch
                    throw new Error("Message too big to fit in a batch");
                }
            }
        }

        // Send the last created batch of messages to the topic
        await sender.sendMessages(batch);

        console.log(`Sent a batch of messages to the topic: ${topicName}`);

        // Close the sender
        await sender.close();
    } finally {
        await sbClient.close();
    }
}

// call the main function
main().catch((err) => {
    console.log("Error occurred: ", err);
    process.exit(1);
 });

It works fine on my side.

This is the API reference:

https://learn.microsoft.com/en-us/javascript/api/@azure/service-bus/servicebusmessage?view=azure-node-latest