For TRIM to be enabled when using SSD's in a raid 0 config you need 2 things to achieve TRIM.
First and most importantly you need Intel Raid OROM 11.2 or newer (The OROM is part of your bios and can be updated via a bios update). Intel only officially supports TRIM for raid 0 SSD on its new 7 series chipset but this does not mean it can not work on older Intel chipsets ie P67/Z67 (there may be other chipsets that can have the 11.2 or newer OROM added to them), if you can find a custom/modded bios that includes the Intel Raid OROM 11.2 or newer (current is Intel RAID OROM 22.214.171.1242) and install the Intel Rapid Storage Technology 11.2 or newer driver (current being Intel RST 126.96.36.1993) you will obtain TRIM for SSD raid 0 arrays.
Here is a link to the forum I found that provides modded bios' for ASUS / ASRock (chipsets available for raid OROM update P67/Z68/Z77) motherboards - ASUS / ASRock BIOS's with updated RAID OROM(this link also contains the download link for Intel Rapid Storage Technology 188.8.131.523 driver) Make sure to read the forum, it gives instructions on how to install the modded bios as well as other important information. I only have done this with Asus Sabertooth Z77 motherboard but it is the same for all the Asus Z77 motherboards, I do not have experience doing this with any other motherboard manufacturers. In order to install a modded bios you HAVE TO flash the bios via the USB Bios Flashback utility, this will require you to put the modded bios file on a usb flash drive, rename the bios file (for the Sabertooth Z77 I had to rename the bios to Z77ST.CAP, each motherboard has a specific file name and the USB Bios Flashback will not work if that file name is not exactly correct, you will not damage or break anything if you use the USB Flashback Utility with the wrong filename for the bios, it will simply not work). In order to take full advantage of the new OROM features, such as TRIM, you need to destroy and recreate your raid array, then you will need to do a fresh install of Windows 7 (Do not use an image instead of doing a fresh install). After Windows is installed and you have finished installing your drivers along with the Intel Rapid Storage Technology 184.108.40.2063 driver you will be all set to enjoy TRIM support on your Raid 0 SSD array.
If you have been using your SSD's in a raid array without TRIM support, I recommend that you perform a "Secure-erase" on each of the SSD drives, this is a different secure erase then what is traditional used on HHD's to completely erase data. I have personally done this to both my SSD's on my primary home computer and experienced no issues and it did return my SSD performance back to how it was when I originally installed the SSD's - HOW TO GET YOUR SSD PERFORMANCE BACK - The link will contain instructions on how to perform a secure-erase on your SSD, you will be using Parted Magic and unetbootin to put Parted Magic on a bootable USB (unetbootin is actually an incredibly useful tool because it will allow you to take ANY bootable .iso file and create a bootable USB flashdrive)