Two actions can come out of one button press with third party tools, what it states is false "Controller remapping: You cannot bind two actions to a single button under any circumstances." utilities like: joytokey, antimicro, & GlovePIE can change what halo sees as input to accomplish this.
Third party utilities can edit Halos bindings to execute more then one action; Yumiris SPv3 launcher is the example here. as i don't own a controller i can't test anything but i will edit to say "You cannot bind two actions to a single button with out third-party tools" with the hope that some one with a controller will write a section on how to do it. lets try to have the most useful information possible here.