What you are suggesting would be good if the pack was useable. I guess I was responding to the many people that have asked about totally removing the IMA, battery, inverter, and converting to a gas only car. The 150 or so lbs that would be removed would make the car lighter.
The key connection here is that the IMA motor/generator is generating voltage whenever the motor is turning, with no loading of the ICE until current is drawn. A built in alternator.
The rest of the IMA electronics are not needed, if you wanted to convert to gas only.
There are numerous ways to use the generated power to keep the 12V system charged. Just have to step it down and control voltage so the 12 v system is not over charged.