Hi
Note that when you select Pan and Zoom from the effects list the defaults are automatically set up....i.e. Start Frame is the full image outline and the End Frame is the central area. Either of these frames can be altered in size/AR/position by selecting the specific button and then clicking and moving the widgets. The preview screen will only show the outline box in the whole frame...not the effect.
The clip will always begin with the Start Frame outline and finish with the End Frame outline. In my version (7.02) there is no provision to use keyframes. The Pan/Zoom encompasses the whole clip/image.
Nat