So, solved my issue - but could I get guidance/clarification on the use of the following two lines:
<address>xx.xx.xx.xx</address>
<localaddress>xx.xx.xx.xx</localaddress>
It was only when both were filled with the IP (non-localhost) of the server that both the public and private login server worked. And, what was odd, is they needed to be filled for the public to work --- regardless of a private login server as well.