Don't worry, you can easily solve this (:
- In animate mode, use the pose tool to select all the bones and meshes you may have.
- On the timeline select all the keyframes by clicking in a place where there are no keyframes and then dragging the mouse to select everything. Just the first row it's fine, it will select everything else by itself.
- The selected area should be blue now, look at the timing, let's say you have a 30 frames animation, go to the left border of your selection the cursor should change to a double arrow, click and drag forward to frame 60 (double your number of frames). Now your animation plays backwards, (in your case, it will play fine)
- click in the middle of the selection to drag all the frames back to the first frame.
Just tested it and it works, I hope I was clear enough, let me know if it worked fine for you too (:
