[Dovecot] Broken NSS Implementation

[Campbell McKilligan]

We're getting this error when IMAP clients attempt to authenticate using 
their aliases rather than their actual username:

Feb ... dovecot: auth(default): BROKEN NSS IMPLEMENTATION: getpwnam() 
lookup returned different user than was requested (campbellmckilligan != 
campbell.mckilligan).
Feb  ... dovecot: imap-login: Internal login failure: 
user=<campbell.mckilligan>, method=plain, rip=82.148.120.110, 
lip=172.20.2.2, TLS
Feb  ... dovecot: child 27345 (auth) returned error 89

For historic reasons, there is no consistency with which username in 
individuals mail client.  NSS correctly returns the name that dovecot 
should use for the purposes of accessing mailboxes etc.

Dovecot-0.99.14 worked fine in this regard - but since upgrading to 
1.0beta3 we have this problem.  It's running on a Fedora Core 4 server.  
It compiled fine with selinux enabled.

Is there a switch to control the response to this NSS behaviour?

Any help appreciated.

Campbell