If you have all limits connected in series and using one input then you just asign that input for every axis, ie if you have X+,X-,Y+,Y-,Z+Z- all connected in series and going in to pin 12 then you set them all to pin 12. Same for the Homing switches, you can actually use a limit switch as a home switch, Mach will only see it as a home switch when you have told Mach to Home, all other times it will be treated as a limit switch.
Hood