How to access LDAP via Natural/CICS and/or Broker

Our Natural users currently logon to the mainframe via 3270 emulation, and we also use Broker to pass data to/from our Java front-end that parses the data and displays on the web.

We are trying to create a single-signon environment by incorporating our existing LDAP that secures the network.

Does anyone have experience in calling LDAP from Natural on the mainframe (CICS)?