How is it possible to set up an A3 page for labels with the ActiveBarcode Generator?
The paper format is determined by the printer (driver). Select the function "Printer SetUp" from the menu "Printer". Select your printer which can print to A3 here. Set the papersize to A3 there. Now you have set the desired paper size and you can set up the label sheet.
Generator: Entering control codes
How can I enter control codes, like a Return?
Switch on the option "Allow control codes" inside the "Options" menu. Now you can enter some control codes in human readable form. Type the control characters within pointed brackets: <CR>, <LF>, <TAB>, <ESC>, <DEL>, <BS>, <VT>, <FF>, <FNC3>. If you need other control codes, you can enter the ASCII value of the needed character as 3 digits within pointed brackets, e.g. <065> for A or <026> for EOF.