secure web-serving with dynamic ip

hi there, i have set-up an apache web-server with mod_ssl, and it all works fine in the intranet.. but if i try to reach it from the outside, it seems to be unreachable... now the ip of my server is a dynamic one of the isp => might that be the problem, because in httpd.conf u have to add a server name and because my server is on a dial up, i dont have a domain-name? .. or would there be other possibilities for secure webserving with dynamic ips? thanks remo