[imp] IMP : SMTP + SASL over TLS

[julien.thomas at enst-bretagne.fr]

Hi dear Horde users,

I have a question about TLS + SASL + SMTP with Horde.
I know that this subject as already been asked before, see for example

[imp] IMP + SMTP auth over ssl/tls
http://lists.horde.org/archives/imp/Week-of-Mon-20060417/044990.html

[horde] SMTP auth with TLS?
http://lists.horde.org/archives/horde/Week-of-Mon-20061002/032041.html

However, both threads present the problem but no solution are provided.

So, here is the question : is it possible to use TLS (enforce = yes,  
use_auth_only=yes) + SASL with postfix.

In horde/conf.php, I have
  $conf['mailer']['params']['auth'] = true
This solve the problem of SASL, if TLS (! enforced & aut_only)

However, with TLS in enforced mode, the problem is that postfix EHLO  
command do not show AUTH LOGIN option until the TLS connexion is  
started (STARTTLS). Thus, when sending mail, IMP failed, telling that  
AUTH LOGIN is not supported, though the tls session must be started  
before.

Is there any kind of option  $conf['mailer']['params']['tls'] = true ?
  or others as I did not found anything about this.

Thanks

-- Julien