The 11.6 OROM appears to have a look up table.
It seems the first word lists the RAID controller Alternate ID (AI) to identify the controller, the second word lists the LPC ID to identify sub groups that utilize the RAID controller and a byte follows to indicate set flags.
For instance alternate ID 1C05 (8086:1C05) is a 6 series mobile RAID controller. This has two LPC sub groups, 1C4B (HM67) and 1C4F (QM67). Bit 0 of the flag byte is set to 1 which I think means SRT support. Where the LPC ID is 0000 I guess this means all sub groups. Alternate ID 1C05 is for the Z68 which has only bit 0 set in the flag byte, meaning support for SRT but not trim. Alternate ID's are a way of identifying controllers that normally use a common ID, i.e. 2822 (8086:2822).
Now you can hopefully see why it appears Intel have made it easy to add other chipsets, they just need to be added to the LUT. For testing however I just overwrote one of the ones in the list.
For the P67 which has an alternate ID of 1C04 I simply used "1C04 0000 07" and like wise for the P55 which has an alternate ID of 3B25 I used "3B25 0000 07".