How can I convert the output from a momentary switch to a pulse on push and a pulse on release?
If you'd like a nice analog solution, there's this circuit that's used by flight simmers:


(source: simprojects.nl)  

The schematic shows the arrangement for a toggle switch, but it could be easily substituted for a momentary.

Each time the switch changes positions, the capacitor has to charge and discharge. During this time, a voltage is developed across the relay contacts, closing the switch. Once the capacitor has charged, the relay turns off again.

More info here:
http://www.simprojects.nl/toggle_to_momentary.htm