T4 cablecheck or DTC0058A schematic?

[pscan.eu]

I am trying (and failing) to connect my T4 to an MGF airbag ECU.
It won't recognise my grey cable as being valid.
I am told that this is because I don't have a DTC0058A adapter between my extension cable and the grey lead.
I don't have a DTC0058A.

Can anyone on here either tell me what's inside a DTC0058A, or tell me how I can modify my T4 to ignore the cable check bit which (I think) would allow me to use the grey cable without the DTC0058A?

My grey cable works on a Freelander alright.

thanks, Philip