This is a long shot but I thought it was worth a try.
We have designed a java servlet running on jboss and authenticating using ldap (edit: via JAAS). Now the customer wants to change to radius authentication for some of the users who uses one-time generated passwords. but still only have the two login fields; username and password. Since we still need user information from ldap, is this possible without sacrificing security? I still need to authenticate in ldap to get the user context. but getting no password I don't see how. Can I make ldap contact radius for some of the users? Maybe I should just say no and make them accept three fields and an additional check against radius after logging into ldap.