This switch works more like a latching relay than a switch.
If you look at the switch from the back with pin 1 being on the top left the connections inside the switch are mirror images of themselves.
So, 4 and 5 are normally closed, as are 2 and 3.
5 and 6 are normally open as are 1 and 2
You can think of it as several switches all in the same container. If the switch is pushed upwards, it changes the state of pins 4-5 and 5-6, but does not change the state of any of the pins 1,2,3.
If the switch is pushed downwards it changes the state of pins 1-2 and 2-3, but does not change the state of pins 4,5,6.
You can think of it as one toggle handle that controls one side of the switch when moving up and the other side when moving down.
Theoretically, since pins 1 and 4 are not used, it should be possible to install the switch 180 degrees out of normal, flip the diode 180 degrees, and use pins 1,2,4,5 to do the same electrical switching as it did originally. That could be a fix if the switch was not operating properly. I say theoretically 'cause it works on paper, but I haven't tried it. A lot would depend on how the switch failed internally.
The same thing could be done for around 20 dollars using two push button switches with one NC and the other NO. One would have to drill a second hole to accomodate the other push button switch. Those switches are at bulbamerica.com and the brand is Morris --7.95 each for NO and NC momentary contact switches.
That again, works on paper just fine, but I haven't tried it yet. The biggest problem I can see is the color of the switches. the NC is red and the NO is black. For the MEP solution the NO oughta be red and NC oughta be black. But if that is the only problem, it is only a tiny, tiny issue.