AGS 10.1 REST api has an Export Web Map task that you can send a request to and get a print output. js api has a Print Task that you can put in your code to make printing easier.
I'm going to assume that the js api Print Task simply calls the REST api ExportWebMap Task. Is that a safe assumption?
If yes, then why is it that the Print Task only seems to support a subset of the things that ExportWebMap does? Like scalebar options, for instance, in the Print Task docs they tell you to set scalebarUnit But in the REST Api you get :