[vchkpw] cram-md5 smtp auth failure.

[N0K]

   Hello, im trying send mail with cram-md5. I send the mails with 
thunderbird, and always take 5 seconds in send the mail, i have seening 
the logs and i can see that, first send the authentication in cram-md5, 
but 5 seconds later it come back to send the authentication in clear 
text. I have seen this with a tcpdump.
   I have using vpopmail-5.4.13, qmail + smtp-auth 
(http://members.elysium.pl/brush/qmail-smtpd-auth/dist/qmail-smtpd-auth-0.31.tar.gz).

   Do i need to patch vchkpw or any similar things ?
   Thanks and regards,
   N0K.