I use web and post servers @ my own IP adress, so where I can place conf. file (like named.conf at BIND) and zone files with NS/MX/A notes at SME?
SME server does not include a publicly visible DNS server. You must use an existing DNS service provider - there are many available.
SME server does have a DNS server for your local network. The software used is tinydns/dnscache, and the configuration is managed by the hostnames panel of the server manager. 'bind' is not used, and there are no zone files.
dem, please take the time to read the Users guide and other documentation. Read it all at least twice.