I must have missed this, but what key do you need to press to get the camera so you see the interior together with the driver? Here is a video of what I mean:
(the camera angel kicks in after 17 seconds)
This is what i read from what the video poster reply to someone ask him about the camera exactly on that video post.
"you have to activate the free cam:
Steam\SteamApps\common\assettocorsa\system\cfg;
open camera_onboard_free.ini
and set to 0 SPHERICAL_COORDS.
in game, replay (or not), press F5 and changes the view as you want with ALT + WASD and others close keys "
So good luck
Edited: By the way looks like "ALT" key is no need. Only WASD + Mouse to adjust the angle. It work for me at least.