[rt-users] LDAP auth: should I still create the users in RT even if I use WebExternalAuth?

[Stephane Bortzmeyer]

I defined $WebExternalAuth in config.pm and now RT no longer asks a
password, it relies on Apache to do so (Apache uses LDAP).

But, if I try to log in as an user which is in LDAP but not in RT, RT
yields:

Not logged in.

Error  
You are not an authorized user

Does it mean that I still have to create the users in RT (may be using
<URL:http://www.fsck.com/pub/rt/contrib/2.0/rtimportldap.tar> from
cron to automatize it)? Or will LookupExternalUserInfo help me?
(Reading its comments, I do not believe it.)

The section "Plugging in your own user metadata" in the Admin. manual
seems interesting but it is currently empty :-}