You need to configure HDToolbox to use the driver of the new card. Select its icon, choose "icon -> information" from the menu, find the tooltype which reads SCSI_DEVICE_NAME=scsi.device and change it to read SCSI_DEVICE_NAME=name_of_the_new_driver. If it's surrounded by brackets, remove the brackets.
I don't know the actual name for the GVP SCSI. Probably something like gvpscsi.device. You can use programs like FindDevice or Scout to find out.
