Oh yea, that condensor on the back of the regulator is to reduce radio interference.
Looks like your wiring is all good.
If I understand what you've been saying so far, your alternator isn't charging and you do not have a gen warning light but an amp meter, when you turn on the ignition switch you have a slight discharge on your meter, when you start and run your car you have a slight discharge on your meter, wiring between your battery and alternator is good, you have constant 12 volts at #3 on regulator, you have switched +12 volts at the #4 terminal, you jumped the field circuit to 12 volts and did not get a spike in alternator output.
When you jumped the F terminal to battery voltage your Alternator should have spiked up to 15 or so volts, if it didn't your alternator is most likely defective. Maybe take it off and take it to a parts store who can check it.
The switched +12 volts through your meter to the #4 terminal supplies power to the regulator which directs this power to the field depending on what the voltage is at #3. after the alternator starts to put out the regulator takes the power from the alternator via the diode trio and uses that voltage to charge the field. At that time the gen light will go out or in your case the meter will no longer show a discharge. It should show a charge as long as the alternator is puting out a higher voltage than the battery.
I wonder if you bought a regulator for use with a gen light and not one used with a meter. If in fact they are different. Seems to me when using an ammeter and not a light the wires to the #4 terminal from the switch and from the alternator 1 are tied together. I'm just going by memory and that may not be the case.