I've no trouble with normal motion tracking, adding clip art to it and having the clip art track, etc. But according to the help in PE8, effects masks are also supposed to be able to be used. According to help:
You can also apply Effects Mask in the Motion Tracking mode. 1. Select a clip in the Timeline or Sceneline. 2. Select the clip, and click to enable the Motion Tracking mode. 3. Select any one of the tracked objects (shown by a yellow frame). 4. Select Edit > Effects. 5. Drag the effect you want to apply onto the tracked object on the Monitor panel. The Effects Mask is applied automatically and the mask moves with the moving object. If you apply multiple effects to the clip, all the effects use the same mask.
I've done that and I get a mask but it does not move with the tracked object. Any hints?