Are you still using Premiere Elements 13/13.1? If so, please remind me of the computer operating system. For now, I will assume Windows 7, 8, 8.1, or 10 64 bit.
The following is a screenshot of the Expert workspace of 13.1. Are those white dots on the Soundtrack what you seek?
Here the rubberband (yellow horizontal line with the white dots) is for Volume Level.
1. Place the Timeline Indicator (red stem with blue head) where you want to place a white dot (volume keyframe). Then click on the diamond below the track name Soundtrack. Those triangles to the right and left of the diamond are used to move the Timeline Indicator to the next or previous white dot.
Just in case articles...
Please consider, and then let us know if you need supplemental information on the above.
Sorry, I should have included that information. I'm using Windows 10 64 bit. I read your solution and will give it a try tomorrow. Thanks for the help (again!)
Thanks for the information. Looking forward to your results when your schedule permits.
Volume keyframes can also be set using Adjust Tab/Adjustments Palette/Volume Panel expanded and the Toggle Animation feature. Have you tried that yet?
Also, see Audio Mixer.
Keyframes in the clip rubbeband can be interesting also.