For M2: Just drag the mirror filter from the video effects box on to your clip in the time line. Then double click on the little mirror icon that shows up in the information box. You will see that the horizontal flipping is already checked...just select the vertical flipping box and click ok. You're done.
Pretty flipp'n cool, huh?
If you are having a difficulty finding any of the boxes they may be buried behind each other . . . go to the upper left of your screen, click on Edius, then layout, then normal.