I'm trying to learn keynote 8 in order to finish off still image files that will go into imovie hd. I'm using the bezier curve tool to make custom shapes to use to mask out the white area that surrounds the images. I have no problem with the tool. And each image that needs masking is on it's own slide.

The Help Menu says to select both the image that is to be masked AND the mask shape at the same time (actually, I'm not certain that I'm accomplishing selecting both, as there's no sign of whether or not the image file got selected when I choose "select all"). Then they say to go to Format>make mask. But no matter what I've tried, all I get for the mask is a square area that borders the outline of the drawn mask shape.

As a test, I created a new slide and used a simple shape from the shape menu, then created another oval shape over it. Same thing happened here -

Anyone have a clue as to what's not working?