Basically you need to convince yourself that there is nothing to fear of this "shadow realm", as it is not real. Sure dreams can be scary while we are in them, but when you wake up you realize that it is just a thought.....an idea in your head. The more you think about this "shadow realm" and the more you fear it, the more you are going to dream of it. So, I would suggest attempting to banish all the negative thoughts about it. Maybe repeat a mantra before you go to bed: "The shadow realm is not real. I control it." Or something to that effect. You can train your waking and dreaming consciousness to have no fear of the place, and take advantage of those dreams.
I don't know if that helps, but please let me know what you think. This is very interesting to me.