Cacti Web Page from outside

[nasked]

Hi:

I just install cacti and works fine. I'm working with a ubuntu server 14.02 and webmin. I manage my server with webmin. I access by local web browser to (localIp/cacti/index.php) without any problem. I need to access cacti web page when i outside my office. I forwarded por 8100 to my server, for access cacti but always browser show me Apache configuration-welcome page. How can i configure Apache2 to access remote cacti manage page(from internet).

Thank You.