How do I use a Key-Alias when trying to use logback with the logstash-logback-encoder and SSL?

Question

I am trying to create a logstash-logback-encoder per the documentation here (https://github.com/logfellow/logstash-logback-encoder#ssl)

<appender name="stash" class="net.logstash.logback.appender.LogstashAccessTcpSocketAppender">
    ...

    <!-- Enable SSL and use a different truststore -->
    <ssl>
        <trustStore>
            <location>classpath:server.truststore</location>
            <password>${server.truststore.password}</password>
        </trustStore>
    </ssl>
</appender>

but I need to be able to use a key alias with the configuration. I can't find anything in the documentation so my question is...

Is it possible to select the key in the key (or trust store) using the alias?