Hi
If VP is working normally and you have multiple audio tracks you should be able to simply select any of the tracks (left click) and choose Fade-in from the right click menu and then enter a duration value. The black volume line along the audio clip should then appear with an upward Fade-in slope at its left hand end.
Re-selecting the same audio clip one more and choosing Fade-out from the menu followed by a second duration should produce another volume slope, this time at its right hand end of the audio clip.
The audio should play with both Fade-in and Fade-out. (Does here)
You should also be able to repeat this procedure for any other or all audio clips on any other track including the main track overlapping or not.
This procedure works OK here with 4.48 and all the clips play with the indicated fades.
Changing the clip speed up however, does prevent a Fade out as you mention. It also seems to happen whether or not the retain pitch box is checked or whether the fade is added before or after the speed change. I would suggest that the fade effect is actually cut off as the clip is shortened with respect to the sound track, video frames being removed to make it run faster.
I checked this out with an 8 second clip having a 7 second fade out. Changing the speed to 110, the Fade out played OK but ended before the end of the clip. i.e. increasing the clip speed truncated the fade out. With a short 2-3 second fade out it is ALL cut off if the clip speed is increased significantly.The volume line is then incorrect as it doesn't alter...BUG
Slowing the speed down also produces a similar problem as the fade-out starts much earlier (probably in its original point) and finishes before the clip actually ends, video frames being added throughout the clip to make it run slower.
I am pretty sure this is a bug. NCH may come in on this if they test.
Nat