Ok, good. A Liberator is designed to manage 4 coils. Typically, they'd be two of one humbucker and two of another. However, it can accommodate almost any pup configuration. Do you know which wires of the Liberator are connected where, in the guitar? Can you take a clear pic?
Or, approach it like this: if two of the terminals are dedicated to the hot and ground of the middle pup, then simply twist bare, green, and white together, and insert them into the middle "ground" terminal. Then twist red and black together, and insert them into themiddle "hot" screw terminal. The exact terminals use will be determined by whomever installed the Liberator.
When I say "middle", I don't mean the physical middle screws. I mean, the terminals that correspond to the middle pickup.