Strominacup - couple of reasons your camera likely has a switched live plus permanent live, one is so that it can do a "parking mode" recording, or more likely (especially if the camera unit does not have an internal battery), so that it can gracefully shut down and save the last bit of video to the SD card without corrupting it.
If unsure, I would wire it as per the manual, red and black to the battery, and use Bigpie's fuse box to trigger the ACC wire.
The advantage of this is that the ACC wire is not likely to draw any significant current, so you could put something else in the same hole too.
