Well..

You can't change a corner point into a control point. You have to delete the corner point and eyeball your way along by adding control points.

http://moi3d.com/2.0/docs/moi_command_reference4.htm#addpoint



...or you could use the REBUILD command, which reconstructs the given curve by sampling points and generating a new curve through those points.

http://moi3d.com/2.0/docs/moi_command_reference10.htm#rebuild



...to get rid of any corner points, use the #Points Mode. Uncheck 'Keep corners' and fiddle with the Point count to get a satisfying approximation of the original curve..pretty straight forward.



in this particular case (the gap thingy), there must be something special going on..