I'm shure you'll have the Crossfire repair manual.
Because i only have the german version i'm not quite shure if i the page numbers and chapter are similar to the english version. In chapter 8E page 45 in my opinion there is a relevant hint that says:

If SCREEM or engine PCM was exchanged you have to reprogram the BCU and the hand transitters (RKE).
Else you couldn't start the engine.

There is an exact description what you have to do in the repair manual.
To do it you'll need a DRBIII device that allows you to check and reset all errors.

I think you're real close to success.
Regards

Markus