Another port forwarding question

I have a web server at 192.168.1.104:80. I forwarded port 80 and I can access the host from anywhere by entering my public IP.
But I can’t ping the host from my local network using the public IP - only using 192.168.1.104 address. What do I have to do to access the web server from my local network through the public IP ?

 0   ;;; default configuration
     chain=srcnat action=masquerade out-interface=ether1-gateway 

 1   ;;; WWW
     chain=dstnat action=dst-nat to-addresses=192.168.1.104 to-ports=80 
     protocol=tcp dst-port=80

http://wiki.mikrotik.com/wiki/Hairpin_NAT

HTH,