[Zope] Zope, Apache, REMOTE_USER

I'm using Apache 2.0, and I cannot find a solution to passing the value of REMOTE_USER from Apache to Zope when using a rewrite rule. I have Apache rewriting requests for Zope, and hooked into Tomcat with mod_jk. My users login through a servlet, and Apache has REMOTE_USER available to it. But any subsequent request to Zope loses this value. I used to have this all working when using FastCGI, but I'm hoping to use only mod_rewrite. Is it possible? Thanks, Rob