Actually I am using a video clip I created in After Effects. The clip starts out all Black and wipes to White. Using the Track Matte, found under the Keying tab in the Video Effects palette, it is supposedly possible to Transition from one video clip to another. I originally found out about this when I purchased an Editors Toolkit from Digital Juice, which came with a number of pre-made Transitions. They offer directions on their website which is exactly the same as the Help Menu in Premiere.
To apply the Track Matte key:
Add the background clip to a track.
Add the clip you want to superimpose to any track higher than the track containing the background clip. This is the clip revealed by the track matte.
On a third track, add the track matte clip.
In the Effects window, expand the Video Effects bin and then the Keying bin, and drag the Track Matte effect to the superimposed clip.
In the Effect Controls window, click the triangle next to the Track Matte name to expand it.
For the Matte option, select the video track that contains the track matte.
In the Timeline window, hide the track containing the track matte by clicking the track’s Eye icon.
Adjust other options as needed.
Composite Using
Select Matte Alpha to composite using the values in the alpha channel of the track matte. Select Matte Luma to composite using the image’s luminance values instead.
I used the Luma option. Hope this helps some. I