Bios Mods -The Best BIOS Update and Modification Source

Motherboard: Asus P5V800-MX
Bios: https://dlcdnets.asus.com/pub/ASUS/mb/so...S-0901.zip

I'm not sure if it is the right forum, I have this situation:
The motherboard teorically support SATA2 but in practice is bugged and doesn't recognize the SSD (and SSD doesn't have the jumper to limit to SATA1 that fixed a similar problem in another pc).

As workaround I have bought Promise SATA300 TX2plus but although the BIOS apparently recognize it then Windows doesn't recognize it (after loading the correct driver in the Windows 7 32-bit setup).

When I start Windows 7 32-bit from an IDE HDD (for testing the problem), then Windows doesn't see the controller Promise SATA300 TX2plus (so I can't install the driver), but it is really strange because at startup:
- The BIOS of the controller appears and detect the SSD correctly
- In the BIOS of the motherboard the controller appears and it is even bootable

So I'm asking if it is possible one of these things:
1) Update the option ROM of the integrated controller of the motherboard to correctly negoziate with new SATA devices
2) Discover and fix the compatibility problem with Promise SATA300 TX2plus
3) Lockdown the internal SATA controller to SATA1 in the BIOS (possibly avoiding the problem)

I will be satisfied with just one option although having both 1 and 2 would be better and leaving option 3 only as last resort.
PS: I don't need RAID but I need AHCI if possible.

Thanks in advance.