extra comm ports

Hi I am having an bit of trouble with setings up two other serial ports within suse 7.1 i have an siig i/o 4s expander and just want to use com 3 and com 4 on it have it set as com 3 0x3e8 irq 5 com 4 0x2e8 irq 7 and when i run setserial and then do dmesg | more they are listed all 4 coms but com 3 and 4 have irq's listed as 3 and 4 like com 1 and 2 does i have try auto config and manual config but seems com 3 and 4 still wont work can someone maybe tell me what i am doing wrong and how i am suppose to do it thanks in advance Bob