[exim] Failed reverse_host_lookup

Hi,

I'm french and new on this list and I use exim4-daemon-heavy on sarge 3.1.

I use some warn acl to define which mail needs to be greylisted,
specialy this acl :

   warn
     !authenticated = *
     !hosts = :
     !verify = reverse_host_lookup
     set acl_m0 = Filtre-reverselookup

But when the dns-reverse-lookup failed, I get an error :

2006-01-21 12:06:52 H=(XXX.XX) [XXX.XX.XXX.XXX] Warning: ACL "warn"
statement skipped: condition test deferred: host lookup deferred for
reverse lookup check
2006-01-21 12:06:54 1F0Ga5-0005zM-Cb <= lianneshoulders@???
H=(XXX.XX) [XXX.XX.XXX.XXX] P=smtp S=1316
id=4f6c01c61db1$1f6557b0$885feceb@lianneshoulders
2

And the message is accepted.

I would like the warn acl still match when there is dns error and
message greylisted with acl_m0 variable.
I searched and find about the "dns_again_means_nonexist" directive, but
I don't think how this one can be usefull.

Can you help me about this problem ?
Thanks.
Samuel.