Disable Plaintext Authentication in James 3.0.1

[Song, Jeff]

Hello.  Is there a way to disable Plaintext Authentication in James 3.0.1?  My 
understanding is to enable TLS, if we want to disable Plaintext Authentication. 
 The other possibility is to disable authentication, but then it would 
essentially make the mail server an open relay.  When we enable TLS, I'm unable 
to receive emails from external mail servers.

Thanks,

Jeff