[Therion] Page Size

Hello, how is it possible to "say" Therion to make a PDF-File with for example a Size of DIN A4 (21 x 29,7 cm)? I have tried Page-setup 21 29.7 20 29 0.1 0.1 cm it doesn`t work I have tried Size 21 29.7 cm It doesn`t, too The command is ignored. Greetings Markus