You'll probably need to contact Compaq because I don't believe that's something they include with the normal specs.
But if you're running a half decent OS (i.e. Linux, NT, etc) and you're not booting off of the disk it should just work, because they'll talk directly to the IDE controller ignoring what the BIOS thinks. The only thing this won't work with is drives over 127G because that's an IDE limitation, you need a ATA/133 controller to get around that one.