Motion tracker question

I'm not a Motion expert so I apologize if this seems like a stupid question.

I have a shot of a person holding a cell phone. I want to replace the image on the cell phone screen with a still image I have.

I imported the phone shot into Motion and used the behavior: Analyze Motion on it.
I then took the jpg and told it to match the move (using, as a source the Analyze Motion).

It worked perfectly except for the end frames when the person lifts the phone. It creates a huge amount of blur that the motion tracker can't follow. (And, I need that bit of motion to make the cut to the next shot work).

No problem I thought. I assumed I could just manually set key frames for the last few frames. The problem is, when I have the motion tracker on, it wont let me use keyframes -- it somehow turns off the ability.

Also, the motion tracking behavior is not a distinct layer. I thought I could just have an end point and turn it off when I was done, but no - it analyses the entire shot (like the optical flow filters do) and I cant turn it off for one region. (It puts a cog wheel next to the layer but thats the only indication it has been tracked)

So, I guess what I'm asking is how would I turn off the motion tracking or over ride it for a while while I manually keyframe in certain areas?

If you want to see what I mean heres the shot, the jpg and the motion file:
[homepage.mac.com]

Thanks

David

Saw your post on the Apple forum as well.

The Analyze Motion behavior DOES lay down keyframes - with it selected, go to the Keyframe editor (Cmd-8) and you'll see them there. You can simply move your playhead to the one you want to adjust, double-click it to enter a new value, or scrub the hot slider off to the left.