You would have to tell clients to download a map pack.

Like they do on this server:
/connect maplounge.net 11110

There is no other way to send maps in gamemodes other than coop editing, you could always add that functionality to the other modes by modifying the servers code, but chances are it would result in your server being delisted/banned from the main masterserver.

You'd have to ask someone that knows more than me if it's allowed.