Hi.
You should not have to change anything in the source code to mess with the margin. In the Receipt Designer you can simply move all the receipt elements, 1,2,3 or more characters to the right. If you need more space pr line (more characters pr line) you can right click each of the section panels in the designer in AX (header, lines, footer) and change it from something else than 44 or 56 which is most common.
Regards,
Hrólfur Gestsson