I just get this exception. No comment :(
: Unhandled managed exception: The requested feature is not implemented. (System.NotImplementedException) at MonoTouch.UIKit.NSParagraphStyle.set_LineSpacing (Single value) [0x00000] in /Developer/MonoTouch/Source/monotouch/src/build/compat/UIKit/NSParagraphStyle.g.cs:19