Floh mentioned selecting all the control points at once in an earlier post. I'm trying to do that with no luck. It seems I can't select a section and have to select each individual point in order to animate a matte.
Instead of selecting all the control points, simply right-click on either the spline name (under Shapes in the Curve Editor) or the "Control Points" nested within the Spline, and select Add Keyframes.
This adds keyframes to every parameter to every existing node. Once you do this,any further changes are automatically recorded.
Be careful, however, when adding new points to an already animated spline, as you'll want to do another global "Add Keyframes" to nail down the new points (or, you can open each one up, and painstakingly choose the individual x and y values, etc. to set keyframes that way.
Also, the righ-click menu for Spline and Control Points includes a Remove Keyframes. That refers to removing all keyframes for that spline at that particular point in time (It's not a global-deletion of all keyframes).