That is crazy $$ for that tool! I had to look up what it does to justify that type of money and all it is are some pins, that are represented as dimples in the above pic, that fit into a lock ring that holds the disc brake adapter in place.
A specialized tool for sure that isn't useful for anything else I can think of nor relates to anything I know of in the bicycle realm. I would try a pin spanner like this:
Would only grab two of the holes but if you are careful to wallow the holes out, you'll have three chances....., it should work and be alot cheaper!