I own my Fusion 12 since February 2013 and as far as I know there's absolutely no way to use the Fusion's onboard knobs to control analog input trim of the recorder. They either work as faders after AD conversion, or can control analog input trim on remote Zaxcom transmitters/recorders via wireless Zaxnet. The only way to get tactile control of Fusion's trims is to attach an external Zaxcom control surface, which, I guess, is not convenient in SFX recording scenarios. I just use the touch screen trims.