MILVIZ UH-1 twist axis on collective issue

I'm trying to assign the collective twist axis to a joystick axis using FSUIPC on the MILVIZ UH-1 freeware helicopter in P3D v5. I've sought help on the FSUIPC forum but thought I'd try here in case somebody succeeded in doing this and knows what variable it needs to be assigned to or even can confirm it is possible.