This thread title is now misleading, clarification:

http://techreport.com/discussions.x/18653

Translation: if your Intel storage controller is set to RAID mode, you'll now be able to benefit from your solid-state drive's TRIM functionality when running it alongside a RAID array comprised of mechanical drives. TRIM isn't supported for SSDs participating in a RAID array, however. Intel may add that feature in the future, but it hasn't committed to doing so.

The actual Raid array does not get TRIMed, only single SSD devices connected to the controller when put in raid mode.