Change default config to get access on WAN admin port 80 after reset on lasts versions of OpenWrt

Hello Friends!
Anybody know how to set defaults settings of last versions OpenWRT to get opened the port 80 for WAN access, then, after a reset operation by the user to defaults, I can access the router and reconfigure it?
They are all part of a more big network I admin. Security is guaranty by routing rules and externals firewalls, I dont need to filter port 80 for home routers.
Sometimes the users press reset button and then I must to go at their homes to make configurations.

I was searching, but no luck. Any sugestions would be apreciated, or some post for read.
Thank You everybody!

These topics have been addressed in the forums.
Allowing LuCI / SSH from WAN is recently discussed here -- this is a bad idea if the router is internet facing, but you have stated that you are setting this up on a private network behind another router/firewall.

and if you want to make your own default settings (so that you don't have the 'standard' default settings when you reset the router), you can build your own image, discussed here with links to the wiki for implementing it.