The readme file you refer to must have come from the Aeroworx retrofit.
All aircraft, including those with isg retrofits, should go in the FS9\aircraft folder, not the isg\aircraft folder. That folder is for aircraft IDs and you do not need to bother with those at this stage. I suggest you remove your plane from that folder and do this:
Go to your FS9\Aircraft\Aeroworx Super King Air B200\panel folder. Make a copy of the panel.cfg and paste it in the panel folder. You should get Copy Panel.cfg added to the panel folder. This is your backup if things go wrong. Now copy the retrofit panel.cfg to the FS9\aircraft\AeroWorx Super King Air B200\panel folder. Now re-boot and run FS9. Hopefully you will have a new panel.
_________________ John
|