The solder resist is epoxy and covers traces, but not solder joints. Are you sure the solder joints are covered with epoxy, or if covered with anything, maybe it is an acrylic "conformal" coating. That is usually very thin. Test probes will usually penetrate it, and usually it can be soldered through as the acrylic vaporizes. I would give that a try first. If that fails, a fiberglass scratch brush can be used to remove the coatings. Those brushes are available at any shop that sells auto refinishing materials.