[Dovecot] How to avoid "authenticated user not found" - messages when using multiple Ldap userdbs/passdbs?

[Sebastian Urbanneck]

Following:

We've got a Dovecot 1.0.10 running on Ubuntu Hardy. Till now we used to 
have only mail accounts under our own domain, but since we're also a 
webhoster the people began to ask if there is a possibility to use there 
own Domains in there mail address.

For addressing this we changed our Ldap Tree Structur: users which had 
been there befor remain in there old subtree, new accounts for Virtual 
Domains are located below an "vd=<domain>,ou=domains,..." subtree.

The main Problem at this: old users are used to login only with their 
username and password, new users has to login via their complete mail 
address and their password. This is not going to change in the future so 
I tried to do this:

Using two userdb/passdb - entries, in each case one for the old users 
and one for the new ones. If a user is not found through the first 
request the second is tried. If this failed too, the user gets rejected.

The Problem with this: when not found during the first try the request 
logs an "authenticated user ot found" - message, no matter if trying via 
the second etry is successful.

Is there a way to tell dovecot, that the user is not "not found" until 
__both__ requests failed?

Regards
Sebastian