Heres mine, not an ARB, but same concept. i moved my security horn and made a bracket out of aluminum that i got from home depot.

Here it is mounted.

Heres, the bracket. it was easy to make, i use only a vice, a hammer, drill, and a riveter. i just bought the metel and made a platform. i use only existing holes for the mounting points. then i painted it black. simple, took about 3 hours but it worth it.

Josh