First, I'd like to say, congratulations on getting as far as you have. Flipping centers two at a time in opposite directions is really quite simple and easy to understand, once you get it. Flipping two the same way? I'm not sure if there is another way to do it, but I would flip them in opposite directions then flip the one that isn't fixed 180. Here is a text version since the video version didn't work:
Hold the globe so one of the pieces you are going to twist is directly in front and center. The other piece that needs to twist needs to be in the middle horizontal layer too. Use the middle vertical slice to move the first piece to the top. Twist the top clockwise one quarter turn. Move the piece back down using the middle slice (I think it is typically called M like the right layer is called R, but I'm not sure if M or Mi is up or down.) Now twist the middle horizontal layer so the other piece that needs to twist comes to the front center. Move it up. Turn the top counterclockwise. Move it back down. Move it back to its correct side. (I think the middle horizontal layer is E, but since I don't know whether you need to do E or Ei or E2 to get the second piece into place, I'm just describing it.)
The above twists a pair of centers in opposite directions. To twist one center 180 hold it on top and do the following: U R L U2 Ri Li U R L U2 Ri Li
I wonder what the issue is with the videos. They work for me. hmm...