The limit switch just senses an open or closed circuit. The voltage to supply the optical sensor would have to be powered seperately from the board ( a wall wart would work). See link if it will let you, if not join the yahoo group also. http://f1.grp.yahoofs.com/v1/0HPoSwD...h%20Hookup.pdf
The ss relays will operate via gcode and will also require or share the external power supply mentioned above. If you try to get power from the board I believe it will interfere with the isolation of the Hobby cnc controller and throw a reset. You should be able to connect your relay to any output not being used.