That's going to be a big project my friend. I don't think that there is just one or two parameters that are going to give you the right voltages on pins 30-33. There are many parameters that have to be set. The motors will have to be tuned with the correct acceleration/deceleration, gains, etc.
If you can find someone with the same controller and the same motors, they might be able to give you the parameters that you need - but that might be hard to find.
To do this yourself, you will have to go through the Fagor 8025M/GP OEM(Installation) Manual and look at each and every parameter and decided if it applies to your machine or not. If it does apply to your machine, you will have to set the parameter accordingly. Have you been able to successfully rebuild most of the other parameters for the machine? Do you JUST need the parameters for the X and Y servo controls?
Basically Chapter 4.2 of the Fagor 8025 OEM Manual deals with setting the analog outputs of the axes. It starts on [pdf] page 114 of 286.
To determine how to set the parameters, you will need the technical information about your particular servo motors and servo controllers. If you can find the technical manuals for the Pacific Scientific motors and controllers, they will have some information to help you determine how to correctly set the parameters in the Fagor8025GP.
It will be a long process. The other alternative is to have a trained technician help you (re)do the setup.