Two wire switches normally worked with on switch that slid to change polarity and pushed to activate. To use two push buttons get power to each switch run to each lead then gound each lead. Place a 1N4001 diode on each of the ground lines to prevent the positive from grounding out before entering the coil. Use an ohm meter on how to point the diode in the right direction. I'd mock up first just using a car light bulb and never press both buttons the same time.
There are articles that have the diode used in operating multple switches at one time if you want to read more.
I am not familiar with the Kato blue box.
Diodes are sensitive to heat. Use the long leads and an aligator clip to heat sink. Insulate everything. Shrink tubing is great. Stuff is found at radio shack.
Do you still want to use the buttons?
A safer way would be to use one button to activate a relay that switches the polarity back and forth on each press. My experteese ends here. Good Luck
I can't be sure but if you have just two wires, there might be a common ground somewhere else. If that is true the switches can be connected to each wire and to the positive side of the transformer. It all depends on the switch. I rechecked an old AHM switch and it has 3 wires so the 3rd wire is the ground and the other two feed the separate coils for direction.
If your still stuck, give us some more info. Picture would help.
The answer shouldn't be as complicated as first described.