Setting up serial Printer in SuSE 7.3

Hi, I am using SuSE 7.3 on a PowerMac G3., Kernel 2.4.12. I have a modem connected to the first serial port /dev/ttyS0 and a printer to the second serial port /dev/ttyS1. Unfortunately this second serial port is not recognized by YAST2 so I can not set up the printer because I can not choose the second serial port. Setting up the printer via YAST does also not work ( I choose the printer under yast, and the set the serial speed with the command stty 57600 raw -echo crtscts