13 x 19 is super A3. Not sure what you mean by "A or B?"
Page setup in NX2 offers a number of options, such as A2,A3,A4,A5,A6,B3,B4,B5, all measured in millimeters. I don't see a Super A3 size as a choice. I'm looking for a size that will fill a 13x18 Epson paper. Thanx!