[Zope] apache authentication with proxy -- remote user mode

hello all has anybody got this working: apache with as a proxy should do authentication zope is in remote user mode (as described in the docs, by leaving out the password after the collon in the "access" file) the apache server authenticates succesfully and in the z2.log file i see that the remote_user variable is passed over, but zope always wants to switch back to normal user authentication and wants credentials. (btw. the user is existent in the root user folder) is it possible, that this is a proxy problem, do i need to pass additional information? tia, bernd