I had this exact problem. Only mine was with a new HPUX box. You could set the card manually to 100Mbps but it would reset to half duplex upon reboot. Apparently, there was a patch that was available from HP.
You might check with Compaq regarding this issue. BTW, have you contacted them for tech support?
I know yours is different, but my system has a config file called /etc/rc.config.d/hpbase100conf. It is a config file that you can force it to 100BT. However, in my case this still didn't solve my problem. We had to implement a patch from HP.
I would first look for a config file (you probably already are doing this). Next I would contact Compaq Tech support to see if they have encountered this before and any patches that might resolve this.
