Hacking PERC H310 in IT mode to work with PowerEgde R710 - unable to see the disks

Hi,

I am trying to use PERC H310 in IT mode (like HBA card) in the poweredge R710. I know that officially this controller is not supported but by googling I found some people saying that it works.

I flashed the IT FW into PERC H310. I tried with the Dell FW:

 sas2flash -o -f 6gbpsas.fw -b mptsas2.rom 

and with LSI FW v. 20"

sas2flash -o -f 2118ir.bin -b mptsas2.rom

I didn't manage to get it working. The card is in IT mode and I can see the disks connected directly by the provided SFF 8087 -> 2xSATA cable but I am unable to see any disks from the backplane ( generic SFF 8087 - SFF 8087 cable).

Do you have any ideas how to get it working? Do I need to have a more specific SFF 8087 - SFF 8087 cable or do I need to set up the controller's advanced settings like timing properties to make it compatible with the backplane?