No RAID controller or drivers that I'm aware of will pass TRIM commands to an SSD if the SSD is part of a RAID set. The Intel drivers will pass TRIM commands to an individual non-RAID SSD if the controller is operating in RAID mode for other drive, but not to an SSD which is itself part of a multi-drive RAID set.
If you format and partition an SSD under Windows 7 then it will issue the appropriate TRIM commands to mark unused space on the drive and restore original performance. You can also Secure Erase the drive or use the Intel SSD Toolbox utility.