Instead of using a transition, use an effect (FX).
Click the FX button at the bottom-left of the clip to be faded. The effects window appears.
Click the green cross at the top-left of that window and click the TRANSPARENCY (opacity) effect.
Click the squiggy line at the far right of the word "opacity" - to reveal the animation line.
Click inside the SELECT PRESET box and choose FADE OUT.
Drag the blue line and release the mouse button. Drag the resulting dots (keyframes) left or right to change the duration of the fade, or up/down to change opacity.
Right-click on a keyframe to delete it. Blank space or a blank, black clip can be added between two clips if desired.
