Tomcat - Client Authentication - LDAP

I hope this is the right group...coud not find a Tomcat specific group.

I have successully configured Tomcat for Client Authentication using the key
store approach.
I am now tasked with configuring Tomcat for Client Authentication using
LDAP. Is this possible with Tomcat?

I've done some research on the web and it appears it's possible if using
Apache as a proxy for Tomcat and authentication, but I have yet to find a
way to do it using Tomcat standalone. (Well, actually Tomcat as a managed
service in JBoss).

Any help is greatly appreciated.

Thanks,
Mark