Solder on a couple of legs from LED to reach the positive and negative terminal. Creative bending and extra solder at right angle corners help add strength.
I put a piece of foam in the battery tray to have a flat surface, from which you can use fiberglass carpet tape as I have. Or velcro as you see fit. The battery actually get's secured up against the plug because the canopy pushes up on it from the rear. You can get creative here if you'd like.
I hope this inspires your own ideas. Definitely share if you have any. I already have a second version that let's you slide the battery in at a diagonal with the board and plug towards the nose of the heli. This requires cutting a slot in your battery tray to securely hold the battery charging circuit board at the right angle. Some people might prefer that orientation better. When I get a chance, I'll mod my second heli this way as proof of concept.