im using m0n0wall for internet sharing in my dsl

i have a static ip address given by my isp.

public static ip: 203.190.x.x
m0n0wall ip: 192.168.1.1
dhcp range: 192.168.1. 2 - 192.168.1.50

windows pc (192.168.1.3) with file server installed
i can access the file server  inside lan by typing
http://192.168.1.3:1400 in browser

but when i type http://203.190.x.x:1400
its not accessible.

how can i make it accessible outside lan?

thanks