To submit any changes you've made to m0n0wall, post them to the forum or email them to Lee directly.

It's best to post them to the forum, as that way if they do not get included in the base m0n0wall for some reason, they are available for others to use who might find them helpful. It also can allow others to show enough interest that it ends up being included. (And prevents things from being lost in e-mail)