In that case check this out:
http://www.digitaljuice.com/djtv/detail.aspx?sid=863A wipe/swipe is apparently quite different. These are used to transition from one slide to the next.... or one part of a slide to the next.
The magic mattes are, in essence, something that adds an effect to an image while acting as a mask to a layer. The demo doesn't deal with these mattes as a transition or a wipe. So, I can't speak to them. A transwipe (at least what I have) is simply composed of the alpha and the non-alpha layers. The alpha version masks the non-alpha version (which is full color ... the alpha layer is grayscale... and your mask mode will be a grayscale mask). Those versions of wipes/swipes that are effectly like double alpha masks are those that have a matte version as well as the alpha . . . the matte is used as a grayscale mask for the destination image layer.
Dale
Update. I've been playing with transwipes .... the danged "alpha" mov seems to be nothing more than a white layer . . . useless. But, the transwipe layer itself seems to be just like the Magic Matte stuff. You simply make the transwipe as the grayscale mask of the destination layer ... as the transwipe progresses, it reveals the destination layer over the source layer. (GADS, I haven't played with this stuff in years!).