qmail and mx records

[ik]

Hello,

I have a qmail (smtp) server . When there is a domain that only the MX
records provides the other side smtp servers, qmail does not check it,
and reports that it can not find any smtp servers.
Using simple telnet on such servers, they do answer properly.

I can't figure out how or what should be configured to make it check mx records.
I can only find how to set my own MX records for qmail, but not how to
make qmail look for the server it is sending.

Please note that I can not install postfix or exim, as normal smtp
servers, so I have to solve this issue with qmail

Thanks,
Ido