1) On your timeline, add your first scene(clip), then click on "Power Tools" and select Video In Reverse.
2) With your clip now reversed, add your colour board(usually black but any colour that takes your fancy can also be used) and set 10 seconds for the duration. The Mirror transition is then inserted between the reversed clip and the colour board.
3) Produce(render) the clip.
4) With the clip now rendered, bring the new render into the timeline(remembering first to delete the original material from the timeline) and, selecting from "Power Tools", Video In Reverse, this will restore the forward motion of your clip but it will now have the "Mirror" effect operating in reverse to open the scene rather than closing it.
5) Now simply continue adding the rest of the clips to make up your movie.
Using the above as a guide, experimentation with other transitions will reveal some more possibilities for role reversal effects on these transitions. It's up to you now to "dabble" and see what you can come up with for yourself.
Cheers!