Is MouseCursor no longer property that can be set with REALSetPropValueObject ?
I have checked that I get value when obtaining System and I get value when obtaining Cursors and I get value when I get specific cursor.
So that leaves this one presumably:
REALSetPropValueObject((REALobject)instance,"MouseCursor",cursor);
Note that if I toss out event at same place in the code and code from there
does me.MouseCursor = System.Cursors.SplitterNorthSouth
Then that works. Which again points to
REALSetPropValueObject((REALobject)instance,"MouseCursor",cursor);