QNX 425, 3com905B or 905C

Hi, I have two systems, both installed with QNX 425, both systems will work with a 3com905B card but not a 905C card. I have several of each type (B & C) and have tried all successfully in windows sytems. I can also see the 905C cards using show_pci, but cannot assign an IP address, althougth when a 905B is used the ip is assigned to the card with no change to the system . Has anyone experienced this before? no a fix?
thanks for any help.