In Softimage 2010, the script is no longer necessary.
[indent]Fcurve Spline Slope Command
If you liked the automatic spline slope from versions of Softimage previous to v7.0, theres a command and preference for you!
The Keys > Spline Slope command in the fcurve editor works in the same way as the Automatic Slope option worked in versions previous to v7.0: it computes the orientation and length of a keys slope based on the interpolation of the fcurve between the previous key and the next key (neighboring keys), but with no plateau influence.
You can also set a preference to have this as the default slope behavior when adding new keys to a curve: select the Keys > Slope Computation Constraint > Automatic Spline (from neighboring keys) option in the Animation Preferences property editor.[/indent]