If you can shut the system down gracefully, you can be able to jog the disks through a simple power-down operation.
You’re correct in that the mirror groups mate RAID1 pairs from each group, as in this example.
If you can get the system off and the drives spun down (also remove power), there’s some hope that they’ll spin up and give the controller a chance to perform an array recovery.
Of course, at the same time, you’ll want to get spares or replacements ready or on the way.
Can you share the specific server model, firmware, OS and other details? There are cases of early firmware revisions of that Smart Array P400 giving false-positive failure indications on drives, so a comprehensive evaluation of your firmware and system health is in order.
You say the Smart Array P400 RAID controller’s firmware version is 2.10 from May 2007. The current version of firmware for that system is 7.18!!
You are severely behind. Also, I suggested pulling the power cables to the system for a few minutes and trying a cold start. Take close note of the RAID controller messages as the system boots. Or does the system even boot properly? Do the physical disks have error lights illuminated?
Can you try a firmware update of all of the components using the bootable HP Firmware DVD just to rule-out bad firmware interactions or a false-positive disk failure?