You can use keyframes to animate the tilt effect.
get your first bitmap in the centre of the screen, set a keyframe at the start with no tilt, one at the end with 90 degrees tilt, then have your second bitmap in the same place starting after that,
then set a keyframe for the tilt effect at -90 degrees at the start and one at 0 degrees at the end.
Then you can move both the bitmap clips to wherever you want using the motion control, or you could move them first, just make sure they're in the same place.
Panasonic SD9, Panasonic NVGS-75, Canon MV600i