Don’t know who can be interested, but i finally flash updated legacy bios, build ssd raid0 and test it - TRIM is working! 
Just in case - motherboard: Gigabyte GA-P67A-UD3P-B3; bios version - F9; changes - updated ‘raidrst5.bin’ to v11.2.0.1527.
P7AUD3P3_trim_mod.zip (1.51 MB)
@JustUser :
Thanks for your report and the attached obviously successfully modded BIOS.
I have moved your post into the much better matching Sub-Forum “Offer: Already modded special BIOSes” and created a new thread for it.
This way interested users with a similar mainboard and RAID0 system may find your already modded BIOS much easier.