IT WORKS! At first I tried the adapter without cross-flashing it to see if it'd work. No surprise; it didn't. FreeNAS didn't pick it up at all.
I followed the instructions here:
http://forums.freenas.org/showthrea...-install-drivers&p=14184&viewfull=1#post14184
It's pretty easy to create the bootable DOS flash drive. Just install the HP DOS flash disk creation utility and extract the Win98 boot disk from here:
http://www.sevenforums.com/tutorials/46707-ms-dos-bootable-flash-drive-create.html
Copy the m1015 flash tools from the first thread and extract them to the root of the USB drive.
If you want, you can automate the whole thing by creating two batch files. In the first one, put in the three commands listed that you need to run before restarting your system. In the second one, put in the last two (including putting in the SAS address from the sticker on the back of the card).
About the SAS address... when you look at the sticker, you'll see that it begins with "500605b". After those numbers and the letter "b", you'll see a hexadecimal address with hyphens ( - ) in it. Append it to the last command line without the hyphens.
Reboot your system (or shut it down and install the card into your FreeNAS box), fire up FreeNAS, and voila! The attached drives show up without any fuss.
Thanks again for pointing out this card to me. I've been looking for a while for an 8-port HBA but haven't been able to find a single one (other than 4-port cards).