The 9400-16e is an HBA with no RAID functionality. Search the PDF for "RAID" and you'll see it isn't mentioned.So a 9400-16e is an HBA 16 external in "it mode" already?
There is no "IT mode" for the 9400. That was a name given to the ability to downgrade a card that had limited RAID functionality to one with no RAID functionality. The 94xx and 95xx come in either HBA (no RAID) or RAID, and you can't change the functionality by flashing firmware.