When you install visual pinball, it creates a program group in your start menu. Just go start visual pinball there. When the window comes up click 'Preferences' at the top then 'Keys' You can remap your keys there. It will apply for all visual pinball or vpinmame tables.
If for some reason you dont have the program group in your start menu, just browse out to where you installed visual pinball and dbl click VPinball.exe.
Note that there is no mapping the keys for vpinmame, just set the keys as mentioned above and it will work for both.