View Mirror Key-frame Animation
How to time- mirror a key-frame animation?
It is the same procedure in many releases, just mirror the keys (check the menu in the timeline).
Note that each track of key-frames will be mirrored only in itself. If key-frame #01 is on frame 30 and the last key-frame of that track on 45, but all others from frame 0-90, then the ones between 30 and 45 will be mirrored only between 30 and 45. (… even if all selected at the same time)
Alternative: You could “bake” everything from the first to the last Key-frame in a Motion Clip. This motion Clip (if set from frame start to frame end) can be then adjusted in the Advanced tab of the Motion Clip with the Spline Curve. (This is a similar approach as the Time-Track, but I do not recommend the time track for complex projects anyway, as one can loose easily the orientation on which track it was applied