I occasionally use a customised special effect template I made few years ago which flys the title or caption into the centre from the left, pauses, and flys off to the right. There are three versions, for top, middle and bottom of screen. I just tried to vary one of them so that it flys in from the right and exits left. I used Edit effects curve, clicking the Mirror button with the (default) option shown selected:
Higher resolution: https://dl.dropboxusercontent.com/u/4019461/MEP-KF-Mirror-1.jpg
But that clearly mirrors not only horizontally (giving me the direction I want) but also vertically, shifting the title to the opposite (top/bottom) area of the screen. I tried the other drop-down options in vain.
Of course, with only a few KFs, I can manually edit the vertical positions, but I'm sure there must be a more elegant method?