I added an AC Commander to a 2343 F3 earlier this year. I don't have any pictures of the installation but what I did was make a mount out of sheet aluminum for the AC Commander. Basically cut a piece of sheet aluminum to cover the fuel tank area. In the front make it long enough so it goes over the holes where the horn battery bracket mounted, drill holes in the aluminum sheet and secure it using the factory horn bracket screws. In the rear have the sheet overhang the rear of the fuel tank, bend the corner up around the E-unit bracket in the chassis, and use the old E-unit screw to secure it.
I did not add Railsounds, as I have a Railsounds 2.5 B unit to run behind the locomotive. I can pop the shell off in the next day ot two if you want to see the bracket I made to mount the AC Commander.