I am looking for a better approach than my current "hit or miss" method for alligning two clips in Vegas 5 using 3d track motion.

Here is the scenario:
My objective in this project is to replace the content of a laptop screen in a clip with some captured screen material. I am having trouble adjusting the perspective of the captured screen material to match that of the laptop screen in the video.

The details:
Clip 1 shows someone seated at a laptop typing at the keyboard. The camera angle is oblique to the screen and there is some light pan and zoom.

Clip 2 is the captured screen action from the laptop (using CamStudio), so the "camera angle" is perpendicular to the screen.

Using the Bezier tool I have masked the screen material from clip 1. Clip 2 is placed beneath Clip 1 so that it replaces the original screen material. However, I find it very difficult to position clip 2 so that the four corners of the screen align properly with the skewed screen position in clip 1. I can get clip 2 into the proper 3d plane without too much difficulty, but then I have trouble getting the proper skew on the clip so that the perspective matches clip 1.

Any suggestions for the best way to tackle this would be greatly appreciated.

TIA, Jerry