Mirroring joint weights in C4D R19


HI ,everyone. I want to mirror the joint weight with new mirroring weight features in R19 . First , I made a half of weights. Then I selected all joints in weight manager, and click Mirror + to - in commands tab . But only leg 's weight been mirrored, the spine joint weight not been mirrored.

Followed this tutorialhttps://www.youtube.com/watch?v=gnTElmPVJAs Anyone can help me?