HI
" I set a fadeout for 1.5 seconds, but the clip fades out in .5 seconds and remains solid black for 1 second. How can I make the fadeout last the whole 1.5 seconds?"
With version 3.6 ( the closest I have ..but this will work in later versions as well) a 1.5 sec FADE applied to the last clip on the sequence is lasts 1.5 seconds but becomes black too soon as you have noted. This probably due to the way the number of frames available are darkened, the range being too short. I think this has been altered in later versions.
The way around this is......
Place a BLACK BLANK CLIP onto Video Track 2 (the overlay track)
Adjust the duration of the clip to 1.5 seconds. (Either drag the ends in to match the time scale over the track or set default image to 1.5 sec beforehand in Options/Media)
Move the blank frame along Track2 until it ends where your main sequence line ends
Right click the blank and select Effects.
Choose the Transparency effect.
In the effects window move the preview scrubber bar to the start of the clip and adjust the slider to 0% Opacity.
Click the green cross to set the keyframe.
Slide the scrubber bar to the end of the clip and adjust the slider to read 100% opacity.
The blue line will now be a diagonal line from bottom left to top right of the keyframe box as shown below.

Click the Apply button.
When you play your sequence now the fade will be 1.5 seconds and will finish black on the last frame.
Nat