H171 - HD3 and IEEE 1394

[Nasho23]

Currently I am using P35 DS3 MB in an Antec 900 Case which has Inbuilt 1394/USB/Audio Bracket. The Labelled 1394 1394 Plug is inserted into #2 USB 2.0 Front USB Header Socket. This Labelled 1394 Plug is same physical appearance and size as the USB Front Header Plugs, but is wired quite differently to F_USB Plug. This was the setup when I purchased the computer. I don't recall ever using the 1394 Front Connection. I am certain Antec would have got approval from GB to setup their case in this manner.
I now want to upgrade my system with a H170 - HD3 MB in the same case and be able to connect the Labelled 1394 Plug into the F_USB Header on the MB. However, the Manual for this MB has a Warning that states this must not be done under any circumstances.
I have contacted GB but the first answer to my enquiry only produced what I already know from the Manual. No reasons why it functions OK on P35 but cannot function on H170.
Has anyone gained experience on this subject.

[dmdilks]

The only thing I can tell you is I wouldn't do that it is wire different. But if you want too look at the header on the 1394 and the USB. Then look at the USB plug and the 1394 wiring diagram. What I would do is buy a adapter card. If you don't wire it right or just plug it in you could short the board out and kill it.