auth_username_translation and LTMP problem

[Arkadiusz Miśkiewicz]

auth_username_translation seems to be appliet on RCPT TO address of LTMP 
transport.

Why dovecot is doing that? 

And better question - is there a way to disable auth_username_translation for 
LTMP but leave enabled for the rest (imap, pop3 etc) ?


Background:

I'm doing
auth_username_translation = @=

to allow logins like aaa at bbb.pl to be internally translated to aaa=bbb.pl. 
That works fine.

Now my exim delivers mail to dovecot using LTMP and it does translation or it 
own, so it does:

RCPT TO: <aaa=bbb.pl at mymbox.pl>

Unfortunately looks like dovecot it doing translation one more time and 
looking in user database for aaa=bbb.pl=mymbox.pl where such user doesn't 
exist. Only aaa=bbb.pl user exists.

Thanks,
-- 
Arkadiusz Miśkiewicz, arekm / maven.pl