Apple Motion 3 - Manual (Page 534)

534 Chapter 6 Keyframes and Curves
Once your set has been created, you can choose it from the Show pop-up menu.
To add parameters to a custom parameter set, do one of the following:
m Drag the parameter from any of the tabs in the Inspector directly into the Keyframe
Editor.
m Click the Animation menu for that parameter, then choose Show in Keyframe Editor.
The parameter is added to the custom curve set.
Note: If Animated is chosen from the Show pop-up menu when you use the Show in
Keyframe Editor command from the Animation menu, a new untitled curve set is
automatically created.