ditch the fly-by-wire, fit a mechanical throttle body.
As far as I know the ECU companies wont let it run fly by wire for some insurance reason. Cable throttle is far better anyway. If going by your avatar, you have a 1.6 you can use a ph1 RSi throttle body.
the omex 600 series does support the fly by wire set up but due to insurance complications in the uk they dont recommend to use it and i should imagine there is a disclaimer on there too!
Then what's your reasoning behind fitting an aftermarket ECU? Cable throttle is a must IMO!