Vegas Help says this is how to change the method of interpolation between keyframes:

The interpolation curve determines the rate of animation between two keyframe settings. To change the interpolation curve, right-click a selected keyframe and choose a command from the shortcut menu. The curve type is updated for all selected keyframes.

What I'd like to do is change the default interpolation method for all keyframe pairs from Standard to Smooth. But there does not seem to be a way to do this. I could not find a Settings value that controls keyframe interpolation (not even in the Internal tab) and the actual <name>.sf file does not contain the interpolation type in any human-readable form (although I'm sure it is in there someplace.)

Does anyone know if there is a way to globally change the keyframe interpolation method?