Is there any way to use Pulsar with schema registry via websocket-/REST API?

I have a Java client consumer that is recieving Pulsar (v2.10.0) AVRO messages (Employees), like this:

import org.apache.pulsar.client.api.Consumer;
import org.apache.pulsar.client.api.Message;
import org.apache.pulsar.client.api.PulsarClient;
import org.apache.pulsar.client.api.PulsarClientException;
import org.apache.pulsar.client.api.Schema;
import example.Employee;

public class TestConsumer {

    public static void main(String[] args) throws PulsarClientException, InterruptedException {

        final String broker = "pulsar://localhost:6650";
        final String topic  = "persistent://public/default/avrotopic";

        PulsarClient client = PulsarClient.builder().serviceUrl(broker).build();
        Consumer<Employee> consumer = client.newConsumer(Schema.AVRO(Employee.class)).topic(topic)
                .subscriptionName("first-subscription")
                .subscribe();
        Message<Employee> message = consumer.receive();
        Employee employeeObj = message.getValue();

        System.out.println("Received Employee: " + employeeObj.getName() );

        consumer.acknowledge(message);
        consumer.close();
        client.close();
    }

}

The topics's AVRO schema is:

{
    "version": 0,
    "type": "AVRO",
    "timestamp": 0,
    "data": "{\"type\":\"record\",\"name\":\"Employee\",\"namespace\":\"example\",\"fields\":[{\"name\":\"name\",\"type\":\"string\"}]}",
    "properties": {
        "__jsr310ConversionEnabled": "false",
        "__alwaysAllowNull": "true"
    }
}

When producing messages via a corresponding Java client producer, all works fine: Messages get deserialized into Employee objects. Now I'm trying to get the same result when producing messages via Websocket API or REST API instead.

For Websocket API producer - I have tried:

ws://localhost:8080/ws/v2/producer/persistent/public/default/avrotopic

with message:

{
    "payload":"CEpvaG4="
}

"CEpvaG4=" is the base64 encoded AVRO binary data (name is "John").

The message is accepted and received by the consumer but throws an exception:

Exception in thread "main" org.apache.pulsar.shade.com.google.common.util.concurrent.UncheckedExecutionException: org.apache.pulsar.shade.org.apache.commons.lang3.SerializationException: Failed at fetching schema info for EMPTY at org.apache.pulsar.shade.com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2050) at org.apache.pulsar.shade.com.google.common.cache.LocalCache.get(LocalCache.java:3951) at org.apache.pulsar.shade.com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3973) at org.apache.pulsar.shade.com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4957) at org.apache.pulsar.client.impl.schema.StructSchema.decode(StructSchema.java:107) at org.apache.pulsar.client.impl.MessageImpl.getValue(MessageImpl.java:301) at com.delti.esb.example.example_consumer.TestConsumer.main(TestConsumer.java:23) Caused by: org.apache.pulsar.shade.org.apache.commons.lang3.SerializationException: Failed at fetching schema info for EMPTY at org.apache.pulsar.client.impl.schema.StructSchema.getSchemaInfoByVersion(StructSchema.java:220) at org.apache.pulsar.client.impl.schema.AvroSchema.loadReader(AvroSchema.java:93) at org.apache.pulsar.client.impl.schema.StructSchema$1.load(StructSchema.java:75) at org.apache.pulsar.client.impl.schema.StructSchema$1.load(StructSchema.java:72) at org.apache.pulsar.shade.com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3527) at org.apache.pulsar.shade.com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2276) at org.apache.pulsar.shade.com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2154) at org.apache.pulsar.shade.com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2044) ... 6 more

Since websocket API does not support AVRO schema registry according to the feature list I guess this is not suprising though.

For REST API producer - I have tried:

curl --location --request POST 'http://localhost:8080/topics/persistent/public/default/avrotopic' \
--header 'Content-Type: application/json' \
--data-raw '{
    "valueSchema":"{\"schema\":\"eyJuYW1lc3BhY2UiOiJleGFtcGxlIiwiZmllbGRzIjpbeyJuYW1lIjoibmFtZSIsInR5cGUiOiJzdHJpbmcifV0sInR5cGUiOiJyZWNvcmQiLCJuYW1lIjoiRW1wbG95ZWUifQ==\",\"properties\":{\"__jsr310ConversionEnabled\":\"false\",\"__alwaysAllowNull\":\"true\"},\"schemaDefinition\":\"{\\\"namespace\\\":\\\"example\\\",\\\"fields\\\":[{\\\"name\\\":\\\"name\\\",\\\"type\\\":\\\"string\\\"}],\\\"type\\\":\\\"record\\\",\\\"name\\\":\\\"Employee\\\"}\",\"name\":\"avrotopic\",\"type\":\"AVRO\"}",
    "messages":[
        {"payload":"CEpvaG4="}
    ]
}'

Response:

{
    "messagePublishResults": [
        {
            "messageId": "10:2:-1",
            "errorCode": 0,
            "schemaVersion": 0
        }
    ],
    "schemaVersion": 0
}

So the message is accepted and also received by the consumer but the payload always seems to be empty when consumed. I tried to get the request similar to the JSON example documented on https://pulsar.apache.org/docs/client-libraries-rest/ but I'm clearly missing something.

Is there any way to get this working?

If not I guess I have to send AVRO base64 without using schema registry and do the deserialization in the application..