Another thing to consider is that when entering pitch bend info in the PRV it can be useful to turn snap to grid OFF. If you don't you will only be able to add pitch bend controllers at the snap to grid setting. To draw in controllers that look like the ones in rbowser's image, which will give a very smooth and realist sounding slope, you might want to change the PRV tool configuration to Paint In Notes/Controllers. Otherwise you will have to enter each controller in individually.
Go to Options>PRV Tool Configuration. Select PRV Tool #2 (Draw) and change its Tool Action to
Paint Notes/Controllers Free (If you want a perfect glide slope you can try Paint Notes/Controllers Linear).
With Paint Notes/Controllers Free you can draw in controllers that look just like the ones in the picture. Don't forget to change the PRV Tool setting back to
Default when you are done.
Ah, just read rbowser's post in more detail... his way is easier... nevermind.

Just consider this a peripheral bit of information.