how to force network card speed


How to force a network card speed to 10Mbits? The io-net (-d sis9
speed=10,duplex=0 -p tcpip) command does not work because nicinfo
show me always that current operation rate is 100Mb/s - full-duplex.
I think that auto-negotiate is imposing this speed. Does anybody know
to force the speed to be only 10Mbits in every situation?