Flash MX 2004.
stroke.curve
Property; a string that specifies the type of hatching for the stroke. This property can be set only if the stroke.style property is set to "hatched" (see stroke.style). Acceptable values are "straight", "slight curve", "medium curve", and "very curved".
The following example sets the curve property, as well as others, for a stroke having the hatched style:
var myStroke = fl.getDocumentDOM().getCustomStroke();
myStroke.style = "hatched";
myStroke.curve = "straight";
myStroke.space = "close";
myStroke.jiggle = "wild";
myStroke.rotate = "free";
myStroke.length = "slight";
myStroke.hatchThickness = "thin";
fl.getDocumentDOM().setCustomStroke(myStroke);