Windows Service & Password-protected Keystore

All,

I see that the Elasticsearch keystore doc here advises that, if a password is used to protect the keystore, that password must be provided each time upon startup. Is there a way to provide this automatically for Elasticsearch installed as a service on Windows? For example, Logstash has the capability to set an environment variable. Is there a similar option for Elasticsearch or the password must be entered manually each time?

Thanks!