I would ask my dealer for help here: You may alter the baseline settings for the screen, but these are given a range in the ordinary setup menu for a reason. Increasing "the light" (as you requested in another thread) could shorten the lifespan of the panel. I know most dealers are happy to guide you so that your BeoVision is correctly set up.
And please beware that even the 7-40 mkII takes a long time to reach max backlight-level. Do you still think it is too dark after 1-2 hours?
Roger