I was logging my last workout on Fitocracy and it included me using a dip machine with assisted weight. (For those unfamiliar, assisted weights counterweight you, making it easier to do said exercises. Kind of like doing pull ups while attached to a big rubber band; it helps you while you get stronger.)
Anyway, the Machine Dip station on Fitocracy doesn't include advanced options for assisted weight. How should I log this exercise? Should I just enter "negative" weight, since Fitocracy knows my bodyweight?