The expander shows in Maxview as enclosure 0, it's just that attached drives don't show up. Also if I connect the same drives directly to the controller they show and work, so I know the issue is not the controller. According to the expander manual, it should be compatible with my controller too.
Does the expander firmware have to be updated through the controller? What if I connect the expander to a pcie port (instead of powering with molex cable), disconnect from the controller and boot from a usb then use fw_tool in something like dos?